You can't really wear bracelets when playing guitar. Well, you can, just not like loose ones so much.

If you wear a bracelet on the hand you strum with, then when you strum, the bracelet will hit against the body of the guitar. And the noise it makes is kinda annoying.

There are also some songs on guitar where you just maybe strum once and kinda pound your hand on the body, and again, the bracelets get in the way.

I don't like wearing bracelets so much, but I use to wear a watch. (And I know I can switch my watch to my other hand, but I write with my other hand and it's uncomfortable for me.) And then I learned a song, and in the song  you just hit the guitar's body a few times, and so my watch really got in the way, so I couldn't play it so well.

What other instrument is there where you can't really wear bracelets/watches??