People should really be solving their own painful problems anyway (always better to be your own customer!) whose solutions can in some way be successfully and profitably exchanged for money.
Best startup ideas are about solving real problems. Some people care about problems getting solved, whether or not they are the ones doing the solving. Keep in mind that no one has enough time to try and solve all the problems at once. So if you see something wrong that needs to be fixed, and you don't have time to do it yourself (because you're busy fixing something else), why not just share it with people, so that someone else might work on it, thus helping to make our world a better place?
Maybe other people are better at implementing someone else's idea than me and I'm just viewing the world through Matt-colored glasses.
What if this is the writers of that new Silicon Valley comedy show soliciting ideas for their characters w/o having to pay writers!?
This reminds me of something Paul Graham called "sitcom startup ideas" in a recent post.