I get real SP-like. My best friend is ESTP, and I think he really strengthened my inferior functions.
But yeah. My interests change really fast. I get interested in things quickly, and I lose interest just as quickly. Pointless, meaningless, time-passing activities, such as Tetris, games, basic procrastination...it gets really hard for me to do work seriously. I also rotate interest in community-based things; I left this forum for a while, then came back, but I'm neglecting my deviantART....eventually, I'll switch gears, not come on here quite as often, and concentrate on another instead for a while. It rotates fairly regularly, actually.
Normally, I would also withdraw and stay in my room or somewhere else I could chill. There's always people at my dorm, though, so it isn't a complete withdrawl.
Anymore, though, I hang out with my ENFJ friend, because I can feel as if I'm withdrawing by being with someone; he understands me in that way. That's real nice. My ESTP friend and I never have an awkward moment, but the ENFJ and I can talk about more things and understand each other more naturally.