Natural joins also automatically break your queries when two columns happen to share a name but not the same meaning.

Step 1: use natural join. Life is great. Step 2: someone adds a `comment` field on table A. Life is great. Step 3: someone adds a `comment` field on table B. Ruh roh.

I'll use them in short-lived personal projects, but not on something where I'm collaborating with other people on software that evolves over several years.