I don't get why people think it's acceptable or funny to poke people, either. I don't know anyone who enjoys it.
I don't necessarily mind being touched, but I'm always surprised by it. Like it gives me a jolt when someone touches me - I'm not expecting it, it surprises me, but like a lot of people, it's only unwelcome when it's a stranger. The few exceptions are super crowded places like malls, I get so stiff and uncomfortable when people brush past me, and when my roommate drags me out to a nightclub - oh dear God. I cannot *stand* it when people, especially guys, even get near me then. I have no idea why, but in that setting I totally abhor the thought of a guy invading my personal space and touching me, even if it's harmless. *That's* when I get the 'what's wrong with you?' looks. I don't do well in night clubs, so I tend to avoid them.