Physical Danger
You are working underneath enormous heaps of metal with electricity, gas, flames, and chemicals every single day. Don't even get us started on the greasy floors you might slip on. It's no picnic. There's no grass and people will give you really weird looks if you spread a blanket out and eat lunch in the middle of the shop.
You'll be lifting heavy objects and using potentially dangerous equipment, like lifts or jacks. Every single day you risk another burn, bruise from falling parts, puncture cuts, or electrocution. Machines are scary. And back pain. There will be so much back pain (source). But , if you're careful and follow safety procedures, you'll be fine. There will likely be inevitable minor workplace injuries, like scrapes. Just stay smart (source).