My wife was the first one of us to join WW. I followed her a week later. So we're extremely fortunate to have each other as partners in this. She's irritated that I'm losing faster than her, but understands that there are physical differences between the genders that cause that, plus the fact that in terms of raw numbers I have more to lose than she does. But I can absolutely understand how frictions could develop between couples who aren't doing this together. In the past I've even caught myself getting irritated with my brother, who lost a ton of weight quite a few years ago while I was still stuck in self-pity mode. I never did anything to consciously sabotage his efforts, but on some level I resented his success. That's a tough thing to admit about yourself - it's not a pretty trait.

What chasm54 said is interesting, I think. I have a pet theory that people who know you honestly do believe that you're too thin when you're actually at an appropriate weight, simply because they're used to seeing you obese, whereas if they were to see you for the first time at the proper weight they wouldn't give your appearance or weight a second thought. It's all in what they're accustomed to seeing.