Which products are you least proud of?

I gather that many HN members are professional software designers or engineers who have worked on several products. Working on products is a real eye-opening experience because you get to see how the sausage is made. I've always looked to software engineers who've worked on a product to give their opinion on whether they would use it for personal or professional use.

Which product have you worked on that you'd rather not use? Or the least proud of? I'm sure there are are some great stories to be told.