A good magic critic is hard to find. Friends either don't want to hurt your feelings or don't know enough to be helpful. Strangers? Fuhgettaboutit. Look at most of the blogs and talk to most of the members of your average magic club and you'll see the results of this: they think they're Buddha's gift to magic.
Since magic isn't as prevalent as music, acting or painting, most people don't have much, if any, basis for comparison. And since most magicians spend damn little time on their art, ten minutes "routining" my dove pan makes me look, relatively speaking, like a genius.
If everyone is telling you you're the second coming of [insert your favorite magician here], then you have little incentive to work on your act, and then where's the improvement? I think the acts that became incredibly entertaining - the Bill Malones, the Tina Lenerts, the Max Mavens, the Cardinis - actively sought out people who told them they sucked. It didn't stop there, though. They found out where and why they sucked, then they worked to eliminate those weak spots.
Even if you're a hobbyist, performing for your friends down at the bar, don't you want to be a better hobbyist? Don't you owe it to your drunk friends to give them the best experience you possibly can?
I've slacked at times, but I've also had a hell of a time getting honest feedback. I want to improve. I want to be the next Cardini, Dunninger, whoever. So next time I ask you for feedback, don't hold back. Tell me where I suck, and how I might improve. Don't worry about hurting my feelings. I'm a big boy. I'll get over it.