You can just go ahead and have a cat provided you will give it some playing objects to keep it busy during its play time. Cats normally make great companions, particularly for people who like independence in their pets.
Yes, cats do all of those things and it really, really hard to train them not to (well except the hair part. You can't keep them from shedding unless you get a hairless, which is a whole other concern). If you think those are bad trait for a pet, then don't get a cat.
Cats do all those things, and MORE.....PLUS you get to pick their poo out of the litterbox!! YAAAAAYYYYY!!! And then you get to smell the horrid poo aroma coming from the litterbox!!!! YAAAAAYYYYY!! And then after the cat gets done flickin cat litter all over the place and covering it's poo in the litterbox then it comes out of the filthy litterbox and goes and lays on your pillow!! YAAAYYYY!!! Cats are just filthy wrong......but that's just me..8)
If you want one, get one. Don't worry about what your friends say as long as you don't mind cat eccentricities. Yes, they do walk across and sleep on everything; that's what cats do. Cats are pretty clean animals, though (after all, they're always washing themselves) and don't actually shed too much if they have short hair. I have three cats. Maybe I don't notice the shedding as much since I have kids, so I'm vacuuming every day or every other day, anyway. I don't have the smell or mess of a litter box because they do their business outside. I trained my first cat to use the toilet as well. I love cats because they're cute, cuddly and they're independent yet also enjoy snuggling in your lap. They're very nice companions. :)
You can train them not to get on counters, provide them with other climbing posts and window ledges, every time they try jumping on counter carry over to their approved spots. Cats pretty smart, they learn. Hair? Weel depends; my cats don't shed too much( shorthair tabby-domestic mixes) and I brush them a lot so no biggie. Cats are cool animals even if my newest Dog thinks they're just fun chase toys:-).