why is it?

Why is it that I will be an absolute nigel no friends for weeks on end, and then get invited to two or three good parties that happen to be on the same night? Since I've been studing and forgotten who most of my friends are, way too many of my Saturday nights are all about me, the dog, an outdated Australian Women's Weekly and an over-full glass of port. Then, when I've decided to change my name to Ethel and start working in a library again, there will be all these events on.

Why is it that my cheap linen pants decided to explode and create an enormous and spectactular hole in them, when I had to walk past a building site this morning?

Why is it that I can't stop myself from using phrases like 'um' and 'you know' when I want to sound all professional?