Expression: Nothing to write home about

People used to write letters to their families when they were away, and this was commonly called "writing home".

The expression nothing to write home about means "nothing special" and we use it to describe things that are not unusual. I think we use this expression especially for experiences that weren't as good as we expected them to be. Here are a few examples:

Although they enjoyed the evening, the restaurant was nothing to write home about.

E.J. Clark's latest novel is, unfortunately, nothing to write home about, which will surely disappoint the thousands of readers who made her first book such a success.

You: How was the concert last night?
Your colleague: Nothing to write home about.