So I saw a cute little piece which was sadly flawed (like I'm one to talk hurr hurr) I ended up leaving a massive comment on how the artist can improve.
Of course, I'm a little paranoid s/he'll take it the wrong way and think I'm being a jerk - not it, of course, I'm just fond of providing crit.
But the act of leaving the comment made me happy. If s/he improves even slightly I can now claim it was because of me woot :P (joking!)