If you're a parent, you've seen the look in a stranger's eyes when your kids are not perfect, and you remember that you used to judge parents the same way...before you became one. My kids and I have been guilty of all ten things on this list. Nicely written by the Scary Mommy blog.
By the way, now that I'm a parent of older children, when I see younger parents I have to resist the temptation to give them advice. The advice is always the same: We've all been there, don't worry about we think.