So, you were saved last week from a long post re: mean people. However, without going into gruesome details, I do want to mention one thing:
If someone mentions a creative idea to you -- in a meeting, at home, wherever -- don't mock them. I don't care if the idea is silly, impractical, expensive and ridiculous. If you can't say something nice about the idea itself, try this:
That's fascinating! What made you think of that?
How interesting! I don't know if we can make that work, but maybe we can use your idea as a starting point for brainstorming ...
If nothing else, just smile and remain silent. Don't mock. Mocking kills creativity.
P.S. With that off my chest, I can now move on. And that may be the bigger creativity tip today. When something is bothering you, deal with it. Then forget about it. Life is too precious to waste time fretting about other people's mistakes.
P.P.S. Life is also too precious to waste time fretting about our own mistakes. Fix 'em. Apologize if you should. Move on.