Here are mine...
My mum putting hair clips in DDs hair.
Fil is obsessed with mowing our lawn in the summer. Of course it's lovely of him to do but he never tells me he's coming and just let's himself in. Really winds me up and I have no idea why.
Another Fil one.
Whenever he comes over, if there are any dirty dishes in the sink, he insists on washing them. You can't stop him. The problem is that he doesn't actually wash them. He kind of dips them in the dirty water they've been soaking in, then puts them straight on the drainer.
Of course I wouldn't ever complain about these things and I'm definitely BU to be annoyed.
So tell me about the small things that shouldn't annoy you, but do.