Experience is supposed to be somewhat proportional to age so your sig is in contradiction with your excuse ;-)

XP is indeed set up in part to encourage voting but (mostly) doesn't dictate how or on what criteria people vote.

Voting a node down because it amuses you is probably fairly unusual (I'll try not to be amusing here). Voting a node down because it is annoying is probably fairly common, but may not be a good criteria - an annoying node can be correct and enlightening.