Why is it one night on Napster you cant find one of the stupid songs you want and the next you find almost all of them?

Tonight I am downloading/have downloaded:

Swing ~ Ani DeFranco
Bobby Fischer ~ Lazy Susan
Love Sweet Love ~ Morcheeba
The Crystal Lake ~ Grandaddy

Also want a couple of other songs but can’t recall band names or song titles so I am stuffed! 🙂