Here are a few examples:
- All that glitters isn't gold.
- Don't get your knickers in a twist.
- All for one, and one for all.
- Kiss and make up.
- He has his tail between his legs.
- And they all lived happily ever after.
- Cat got your tongue?
The most recent place I hear this is at the end of every episode of People's Court, a show I sometimes watch in late afternoon if I have nothing else to do. On People's Court the parties are interviewed by the host after the case. Every single time the losers can be heard lamenting it is what it is.
I suppose it's only natural that we use clichés so much. They get the point across and it saves us from having to think of something original to say. And there are certainly worse things to worry about. I guess we'll just have to get used to them. They'll never go away. It is what it is.