Just had my PIL for tea and DS1(7) and DS2 (6) were little monkeys..
They weren't being really badly behaved they were just a bit loud and silly, (and ds1 got the hump when i wouldn't let him go on the playstation) they were playing up at the dinner table too ...
DH wasn't even here - he was at work, PIL asked if they could come round to us and collect the DC's from school with me - then they stayed to tea.
I just find it all a bit stressful, DD1 is 2 years and she is a bit of a handful and then i'm trying to cook shepherds pie and be sociable etc...
PIl are just so bloody polite and quiet and 'nice' - I always feel like we are so loud and rowdy with them!