My most used word is probably whatever.
I think procrastination is an excellent word as is discombobulate.
My favourite word today is donut. I've been calling everyone a donut today!
We have a girl at nursery who is half Dutch and she was teaching me some today. She said her favourite Dutch word was 'tafel' (that's what it sounded like, I have no idea how to spell it!) It means table! Lol!