[savoytruffle]

Of course in the days of the Sad Mac, that was only upon a failed boot. When it crashed it showed a cartoony round bomb with a lit fuse on the end. Made people mad!

[stevenbedrick]

I've always liked Neal Stephenson's description of the little bomb icon:

"When a Macintosh got into trouble it presented you with a cartoon of a bomb, which was funny the first time you saw it."[1]

1: http://www.cryptonomicon.com/beginning.html