My biggest thing when working at AOL was no upward mobility. If I wanted to manage developers, literally 70-80% of my time would be sucked into the ether with meetings and product reviews. There is so much management overhead there that it's a nightmare to actually get anything done. Once you manage even just one person, you're going to have no time left to do what you actually like (and are probably good at): programming.

So why not go to a smaller company where people listen to your ideas and you're able to do what you love and make a difference? I think the thing people want the most is to know that they're making a difference. This is nearly impossible at a large company.