I hate having people in my room too.
They eat like sweets and stuff right, then I pass the bin around for them to throw rubbish away, and after they leave I just find wrappers all over the floor. Like, seriously, you didn't even have to get up, you just had to pick up the wrapper and put it in the bin.
Also I leave the room for like 2 seconds to get pizza or whatever and they're all snooping around my room. Literally like looking under the bed and in my wardrobe and all that. They also rearrange all my stuff. I have a dressing table where all my skincare stuff plus medicine is and one night after my friends had left I had an asthma attack and I couldn't find my inhaler.