best / worst comment

An old thread a stackoverflow, asked for “What is the best comment in source code you have ever encountered?“. Some answers are must-read :

// 
// 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
// 

or

// somedev1 -  6/7/02 Adding temporary tracking of Login screen
// somedev2 -  5/22/07 Temporary my ass