"503 Polite People say HELO first." -- Mail server, responding to a misconfigured client.
"SRV_WHAT_THE_HELL? (0x0064) -MikeSegmentation fault (core dumped)" -- A third-party Linux ICQ client (no, I don't remember which one anymore.)
"warning: `class Getstring' only defines a private destructor and has no friends" -- g++
"Uhhuh. NMI received for unknown reason 30. Dazed and confused, but trying to continue." -- Linux kernel