Because if you don't, you can't complain.
Now matter who you are voting for...PLEASE VOTE! It'll only take a half an hour or so out of your day to make your voice heard. These are the elections where every vote really does count (provided the e-voting machines don't fuck up). If you happen to have digital cable with on demand, you might be able to learn about the people running. Or you could go to www.dontvote.com an AARP site with infor from each state.
Mid-terms might not seem as important as presidential elections, but it is, especially this year. Be heard! Make a difference. It's your country too.