- Introduction
- The Good: When Comments Are Your Best Friend
- The Bad: When Comments Are a Liability
- The Hilarious: Dispatches from the Codebase Trenches
- Linus Torvalds
- Conclusion
Code Comments: The Good, The Bad, and The Hilarious
Every developer has been there. It’s 2 PM, you're deep into a feature, and you stumble upon a function named handleData. It takes three arguments: x, y, and flag. It returns 0 or 1. There are no comments. You are now an unwilling digital archaeologist, and your afternoon is officially ruined.
In the world of software development, few topics are as polarizing as the humble code comment. To some, they are the clarifying signposts in a complex landscape, a necessary form of communication. To others, they are a "code smell"—a sign that the code itself has failed in its primary duty: to be clear.
The truth is, comments are a powerful tool. And like any tool, they can be used to build something robust and maintainable, or they can be used to make an unholy mess. Let's explore when to use them, when they become a liability, and those special moments when developers use them to immortalize their frustration.
The Good: When Comments Are Your Best Friend
Good comments don't explain what the code is doing; they explain why. If your code is so cryptic that you need a comment to translate every line, the problem isn't a lack of comments—it's the code.
Here's where comments truly shine:
1. Explaining the "Why" (The Business and Product Logic)
Code is excellent at showing the implementation, but it's terrible at capturing external context. This is the most valuable role a comment can play: bridging the gap between a business decision and a line of code.
// Apply a 10% holiday discount for all premium users.
// This is for the Q4 campaign and must be removed after Jan 31st.
// See ticket JIRA-512 for the official request from Marketing.
if (user.isPremium) {
price *= 0.9;
}
2. Documenting Non-Obvious Solutions and Trade-offs
Sometimes, the "best" solution is counter-intuitive. It might look slow, clunky, or just plain weird. A comment here prevents a well-meaning future developer from "optimizing" your code and re-introducing a subtle, horrifying bug.
// We are intentionally using a simple string concatenation here instead of StringBuilder.
// In this specific context with a known, small number of loops,
// performance tests showed this was surprisingly faster due to lower memory allocation overhead.
// Do not change without re-running the benchmarks.
string result = "";
for (int i = 0; i < 5; i++) {
result += GetValue(i);
}
3. Formal API Documentation (Docstrings & XML Comments)
This is a disciplined and invaluable form of commenting. When written in a specific format (like JSDoc, Python's Docstrings, or C#'s XML), these comments can be parsed by tools to automatically generate professional, readable documentation for your library or API.
def connect_to_database(user, password, host="localhost"):
"""Connects to the database and returns a connection object.
Args:
user (str): The username for the database.
password (str): The password for the user.
host (str, optional): The database host. Defaults to "localhost".
Returns:
Connection: A database connection object on success.
Raises:
ConnectionError: If the connection fails after 3 retries.
"""
# ... connection logic ...
4. "Here Be Dragons" Warnings
A good comment can act as a crucial warning sign about critical, non-obvious constraints. It’s the digital equivalent of a yellow caution tape around a dangerous piece of machinery.
# WARNING: Do not change the timeout value below.
# The legacy payment gateway will automatically fail any transaction
# that takes longer than 2.5 seconds, but it won't send a failure
# response until 30 seconds have passed. This value is critical to prevent
# hanging requests in our system.
API_TIMEOUT = 2.5
The Bad: When Comments Are a Liability
Bad comments are often worse than no comments at all. They create noise, actively mislead developers, and rot over time, breeding bugs and confusion.
1. The Redundant Comment
This comment is pure clutter. It insults the intelligence of the reader by stating the absolute obvious.
// This is a class for a Car
class Car {
// constructor
constructor() {
// ...
}
}
// increment the count
count++;
2. The Zombie Comment (The Outdated Lie)
This is the most dangerous comment. It was true when it was written, but the code underneath it changed, and nobody updated the comment. A developer trusting this comment will be led completely astray, wasting hours debugging a problem based on false information.
// Set the user's status to inactive (status = 4)
user.setStatus(5); // Oops. The status code for 'inactive' changed to 5 last month.
3. The Crutch for Bad Code
Developers sometimes write confusing, poorly named code and then use a comment as a band-aid to "explain" it. The right solution isn't to add a comment; it's to refactor the code to be clearer.
Instead of this:
// This function gets the items from the database (d) and filters them
// based on the user's permissions (p).
function getFltItems(d, p) {
// ...
}
Do this:
function filterItemsByUserPermissions(items, permissions) {
// ...
}
4. Commented-Out Code
In the age of version control systems like Git, there is no reason to leave huge blocks of commented-out code in the codebase. It’s digital hoarding. It confuses search tools, clutters the file, and makes other developers wonder if it's important, disabled, or just forgotten. Just delete it. If you ever need it back, your Git history is there for you.
5. The Rise of the AI Commentator 🤖
You've probably noticed that modern AI coding assistants (like Copilot or Cursor) love to add comments to almost everything they write. This isn't because they're trying to be helpful in a nuanced way; it's because they are trained on billions of lines of public code, where they've learned to associate a specific code block with a specific explanatory comment. The result is that they often produce perfectly redundant comments that explain what the code is doing, not why. The AI provides a verbose first draft, but it's still the developer's job to be the editor—to delete the noise and preserve only the comments that provide genuine insight.
The Hilarious: Dispatches from the Codebase Trenches
Every experienced developer has stumbled upon comments that are less about documentation and more about the human condition. They are small windows into a moment of pure frustration, confusion, or caffeine-fueled delirium.
The "Abandon All Hope"
// I am not responsible for this code. They made me write it, against my will.
The Cry for Help
// Dear maintainer:
//
// Once you are done trying to 'optimize' this routine,
// and have realized what a terrible mistake that was,
// please increment the following counter as a warning
// to the next guy:
//
// total_hours_wasted_here = 42
The Moment of Pure Honesty
// drunk, fix later
The Magic Number
// The problem is that the sensor thinks 29 is 30.
// This is my resignation letter.
var a = b - (c / 29);
The Relic from a Bygone Era
// When I wrote this, only God and I understood what it was doing.
// Now, only God knows.
The occasional masterpiece:
/*
, ,
/ \/ \
(/ //_ \_
.-._ \|| . \
\ '-._ _,:__.-"/---\_ \
______/___ '. .--------------------'~-'--.)__( , )\ \
`'--.___ _\ / | Here ,' \)|\ `\|
/_.-' _\ \ _:,_ Be Dragons " || (
.'__ _.' \'-/,`-~` |/
'. ___.> /=,| Abandon hope all ye who enter |
/ .-'/_ ) '---------------------------------'
)' ( /(/
\\ "
'=='
This horrible monstrosity takes a medicare monstrosity and mangles it
into a data structure that can easily be used to create a medicare feed.
It's bloated, confusing, and pretty awful by necessity(for the most part).
*/
And of course, when you feel too guilty
// I'm sorry.
Linus Torvalds
Before finishing this blog post, I just wanted to mention Linus Torvalds, the creator of both the Linux kernel and the version control system Git. I won’t dive deep into those, since that’s not the focus here, but their rants on both reviews, and comments to code are legendarily known among the community.
// Wirzenius wrote this portably, Torvalds fucked it up.
If you don't know about them, I recommend googling them and their comments. Just for fun, if nothing else.
Conclusion
These gems serve as a crucial reminder: code is written by people. It can be a place of pristine logic and structure, but it's also one of chaos, humor, and shared struggle.
So, the next time you write a comment, ask yourself: "Am I explaining a necessary 'why,' or am I just making excuses for unclear code?" And if all else fails, at least make it memorable for the next person who comes along.