Collocations for selfish - adj.

be, feel, seem, sound
I know I'm being selfish, but I can't help it.

become

extremely, fairly, very, etc.
a very selfish attitude

incredibly
completely, entirely, purely, totally, utterly
These people are completely selfish.

a little, slightly, etc.

Selfish is used with these nouns:
desire, end, interest, jerk, motive, reason, streak