Comments in source code

Honest comments:

// I'm sorry.

// Dear future me. Please forgive me.
// I can't even begin to express how sorry I am.

// I am not sure why this works but it fixes the problem.

// When I wrote this, only God and I understood that I was doing
// Now, God only knows

// If I from the future read this I'll back in time and kill myself.

// I am not sure if we need this, but too scared to delete.

// I am not responsible of this code.
// They made me write it, against my will.

// I dedicate all this code, all my work, to my wife, Darlene, who will
// have to support me and our three children and the dog once it gets
// released into the public

Warnings:

/*
 * You may think you know what the following code does.
 * But you dont. Trust me
 * Fiddle with me, and youll spend many a sleppless
 * night cursing the moment you thought you be clever 
 * enough to "optimize" the code below.
 * Now close this file and go play with something else.
*/

// Magic. Do not touch.

// 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 = 16

Sweet revenge:

// no comments for you
// it was hard to write
// so it should be hard to read

#define TRUE FALSE
// Happy debugging suckers

Exception up = new Exception("Something is really wrong.");
throw up; //ha ha

Plans for the future:

// drunk, fix later

// TODO: Remove this comment.

// TODO: The following if block should be reduced to one return statememt:
// return Regex.IsMatch(strTest, NAME_CHARS);
if (!Regex.IsMatch(strTest, NAME_CHARS))
   return false;
else
   return true;

// TODO: Fix this. Fix what?

Good names and values:

options.BatchSize = 300; // Madness? THIS IS SPARTA!

const int TEN = 10; // As if the value of 10 will fluctuate...

long john; // silver :D

double penetration; // ouch

And few comments by Captain Obvious:

// Increase i by one
i++;

return 1; // returns 1

/*
 * Method declaration
 * @param table
 * @param row
 * @throws SQLException
*/
void addTransactionDelete(Table table, Object row[]) throws SQLException {

/////////////////////////////////////// this is a well commented line

From closed question on stackoverflow