is it a threat if someone tells wewe that they are going to slam your head against a sink even if they are joking?

I've heard worse coming from my younger sister's lips and she's only 7. xD

Hmm... it depends, really. What kind of voice was the person saying the sentence in? If the voice tone was noticeably light-hearted, joking and warm - then it might've been just for laughs.

If the tone was deathly-serious, humourless and straightforward - then the person might have some serious anger issues. au wewe might've done something that really riled them up.

There are many things to consider....

How close the person is to you, whether they've alisema similar things to wewe before, whether they actually ever did any of those awali things, what their history of violence/crimes/behaviours is...

wewe can confide in someone close to wewe and then see what advice they can offer.