I think I am going to make a joke pertaining to boob size.
What is your reason for wanting to make a joke about something like that anyway?
I'm just angry at certain people for having bigger boobs than me.
A lot of people struggle with self-image and things of that nature. But I don't think it's the right way to go about expressing that by making fun of other people. It would be more beneficial the focus on yourself.
Of course it's a fun joke.
Regardless if it's a funny joke or not it could upset that person. Like I was saying, the effort you're putting into telling these jokes would be better off used to improving your own self-image.