I come up with more ideas than anybody I know. A tiny fraction are any good. The vast majority of them are half-baked. As soon as you discover a fatal flaw (and if you're anything like me, you will more often than not), tuck the idea away in your mental file cabinet, where your subconscious will toil away for years, changing this and that, until it goes from stupid to brilliant.
I take criticism from others with a grain of salt, but my own criticism I've learned to trust.
Don't feel bad about having bad ideas, or even mostly bad ideas. It's an essential part of the process of coming up with brilliant ideas.