i think quite a few viewpoints have been given here...so here is mine--
It all depends...i mean, when we're giving a performance/writing or doing anything which requires a feedback for the first time, it does matter a lot! And i'm speaking from personal experience. I like public speaking. People say i speak well in front of people. The first time i spoke on the stage was when i was in 2nd grade. had i not been appreciated then, i would not have gone ahead and won the best public speaker title in my school in grade 4.
Similarly, i posted the first chapter of my very first story a few days back. Had i not received a single positive feedback, i would have never posted another chapter. But, coming back to the point. Once a person is experienced in his/her field, he/she starts taking feedback, +ve or -ve, with a pinch of salt and strives to do better. Hence, i feel all types of feedbacks are necessary as it gives a person humility to understand that he can improve a lot.
Further, the first positive feedback, as i mentioned earlier, is very important. I learnt this in the workshop i'm attending that one should never shy away from appreciating good things and also not be offended by what others think of you (It's a presonality development class, btw).
So, adopt a happy-go-lucky attitude and be merry...Damn the others who say you aren't good, 'cause YOU know you are. But don't damn the ones who give comments and are experienced enough to be your great grandfather in that field....LOL
hot_bsk