I'm sorry this is so long...
I took my 11 month old DD to the park the other day, she loves the train, which has a tunnel on it that the kids can crawl through. One of the mums asked another mother how her son was, and she replied 'oh well, he hasn't bitten anyone yet today'. A few minutes later, my DD was crawling through the tunnel and a little boy of about 18 months - so still a baby really - toddled up and climbed in the tunnel, and immediately bit my DD on the cheek. Badly enough to puncture the skin and make it bleed. It was a few days ago and she's now got a huge purple bruise. Of course she started screaming, which scared the little boy who started crying too. I looked around for his mum, and she was sitting on a bench at the other end of the park chatting to her pal. She came up to get him and tried to carry him away quickly. When I said 'excuse me, he's just bitten my baby', she just looked at me blankly but she couldn't really deny it because of the massive bite marks. Because of the way she was looking at me I added on 'I'm just telling you in case he does it to one of the other kids, you might want to keep an eye on him'. At the time I was thinking not to make a big deal of it - after all it wasn't his fault as he's still very tiny, but she didn't apologise or tell her son not to bite people. She just carried him off and stuck him on a swing. Now I'm really annoyed that even though she knew her son was going through a biting stage, she still let him run around the park unsupervised. And then just ignored the whole issue with him instead of telling him not to bite.
God sorry that is so long. Thanks if you've managed to read this far. Do I just need to chill out a bit and try to overcome PFB syndrome?