Why do we clink glasses at a toast? I’ll use this anecdote a lot over the course of the next week to be a smartass during lunch. This from Kuro5hin:

The vast majority of actions or words we use today are things we saw or heard from others. Many of these things we put too little thought into. Some questions we can ask ourselves can lead to interesting facts. Why do some countries drive on the right and others on the left? Why do we say "bless you" when someone sneezes? Why did rounded knifes appear in 1669? And why do we hit glasses when drinking amongst friends? Answers to these questions and other anecdotes follow for the pleasure of the reader. Some of them are just stories I heard, others I've read in a book or online. In all cases I could be wrong. You as the reader can participate in debunking any of the stories I present.
[kuro5hin.org]