American expressions I still don't understand

  1. Get your shit together
    I mean, I get why you don't want it all loose but why you need to get it together is still kind of a weird saying if you ask me (you have to understand that Spanish is a very literal language and my mom and I are both English majors so we analyze this stuff for the fun of it)
  2. Hop in the shower
    My mom and I still laugh about this one, like the idea of hopping in the shower makes us laugh because it just seems dangerous (but maybe a little fun?)
  3. Hanging out
    My mom and I are always saying "what exactly started that? Why was someone hanging somewhere? I don't understand the hanging part?"
  4. Chill out
    Like, why do you want someone to be cold to you? Can't you just tell them to calm down? Why was the chill ever a need? Again, this one is so weird to us
  5. On a roll
    We still don't understand why rolling down a hill or being on top of a roll would be a good thing
  6. Don't have a cow
    I get that birthing a cow is something no human wants to physically experience, but why a cow? Why not any other large animal?