I got a few dumbass characters, but my guy is my MC, Apollo.
He's 6'3 of stupid, very sheltered, gullible, overly trusting, doesn't think before opening his mouth, never pays attention and doesn't know boundaries. There are times when he thinks he's helping, but is only making everything worse for the other characters (Specifically my other MC, Julian.) Apollo can be smart if he put in the effort to learn things, he's pretty good with music and such. Although due to self-esteem issues, his environment and how he grew up, he doesn't think he's able to learn so he doesn't attempt to. Doesn't help that being an alcoholic has pretty much rotted his brain.