Loki believes he is fundamentally a very selfish person! Though not really more so than Stark, he has probably said on occasion. But he does have something to prove, and if helping peoples helps him do so, well...and it is nice, having people look up to him. No one in Midgard thinks of him as Thor's younger brother first and foremost.

Well. In his Midgard. This Midgard is something else entirely. He's not too pleased about that.