Comment by stevesimmons

I have two favourite bugs, one weird and one dumb.

Weirdest one was an IDE where the colorizer gave up on source lines longer than 998 chars. Instead it rendered the whole line as background, i.e. invisible. I once wasted two hours debugging a program with an invisible line of code!

The dumbest was a postage billing system for a bank using a third party Print-and-Mail company. Somehow the billing system went live adding the previous day's total postage costs to itself, then adding the new day's postage. These expontentially growing totals were then paid automatically by the accounting system each night... So it goes live, ... and a week later Finance gets an alert the account is overdrawn... They actually paid out nearly $1b in postage costs before hitting their internal credit limit with the bank's treasury.