The best excuse ever

Jan Lancaster came up with this one - and I speak as if I knew the woman (I don't). But still, this is the best excuse ever created:
I HAVE SAND IN MY MOUTH. How great is that? It's all encompassing and multi-purpose. You can use it in just about any scenario.

Can you help me finish this report?
I'm sorry, I can't. I have sand in my mouth

Why were you late for work?
I had sand in my mouth

Why are you so bitchy today?
I have sand in my mouth.

See? Works every time. Plus you don't really have to dignify stupid questions with an answer. Just say: Because I have sand in my mouth.