it's not funny

1. I'm being serious; don't treat this like a joke. It's not funny, Dave. You could have gotten hurt, do you understand?

2. Stop laughing at me; the situation is not humorous for me. Hey, it's not funny, guys! How would you like having to go around school all day with a big rip in the seat of your pants?

3. Used at the end of a statement to indicate the extreme degree to which something is true. Just a few years back we were struggling to make ends meet. Now we've got so much work it's not funny! Wow, Lauren's new boyfriend is so hot it's not even funny!