You're playing on words.
I'm playful.
No you are not, but sometimes boring.
Ιncorrect.
Correct. You can't decide it but we can.
Who is "we"? Are you passing a disputeone phase?
We is everybody except yourself. You can't decide you are playful or not. You may just fun by yourself, it doesn't make you playful.
If you do something doesn't let your interlocutor have fun, it doesn't a joke; but an abuse.