Even if he's a little mean, Simon knows what he's talking about and he tells it like it is. That honesty can break fragile hearts, but you know what? It's better to hear that kind of feedback and learn from it than it is to keep unrealistic expectations and wonder why your dream hasn't come true.
When I see a musician (or any artist, really) who is blindsided by criticism or else very defensive, I guess that he or she hasn't had a Simon in their life. It's a rare but valuable person who will tell you what you need to hear.
It can be hard to find someone who will be honest with you about your talents. People who are inclined to love you and celebrate you, like your family and friends, are bias. These people make a great support system, but probably not the best critics.
I love what Alex Day wrote about this a few months ago, too.
"... my audience like me so I don’t trust them to be objective about my music. 'This is great! It’s new music from you!'.... If the people that listen to my music have good ideas about writing music, then they should be writing music. But if they don’t, they shouldn’t. It’s like any job – if there is someone who doesn’t have experience of working in that industry, you don’t ask them for advice. I like cars, but I don’t know how to build a good car. It’s the same thing. Just pick out two or three people you really trust and listen to them. If a band plays a new song at a gig and asks if the crowd like it, of course they are going to cheer. It’s not as if they are going to say it’s shit!"If you believe in your dream, be confident enough to solicit and accept feedback. Too often people turn to "vanity stats" (such as the number of Facebook 'Likes' or Twitter followers they have) for positive reinforcement. But those things don't really tell you why people do or don't like your music.
Find someone who's opinion you trust and ask them to maintain honesty with you, especially before you find your success. As one musician reminded me, "The more popular you get, the more people will tell you what you want to hear so that they can get close to you."