It all depends on the type of club, the attitude of the people and the area you're in.
If I'm walking down my highstreet, I can chat to people and drag them into the nearest cafe if we hit things off. I've never yet been slapped... but then again, if I tried the same highstreet at about 7pm-2am, I'm more likely to be mugged (not by the women) and therefore women don't tend to stop and chat to strangers.
Goto a bar, you'll likely to meet up with lots of HB0-6 who are p1ssed out of their skull and intent on having a good time - they don't want blokes to ring them the next day.
Some clubs are similar to the bars - I don't like the trendy places, it just seems like a place for HB7-10's to walk around, watch the guys drool and be a slut.
I've found a couple of stomping grounds which I feel comfortable, like the music and feel like I can approach people. Some clubs are so socially strict, if you're sitting on your own at a table, no-one will come up and sit down. If they did, the other person would make an excuse and leave (this really has happened). I like a relaxed attitude and can't work in 'pressured' enviroments.
So both clubs and streets & pubs are all the same, depending on if you feel comfortable and so do the others around you.