[Phalanx]

People that don't understand personal space - standing in line at a supermarket and some fool just HAS TO stand right behind you within 1-2 feet.
Same thing applies to people who do this tailgating shit no matter where you are - walking, escalators, in cars...

This kind of carries over to people who "flock", now this is similar to the aforementioned issue but not quite the same, equally annoying though.
The people who say, when you are waiting for a train, on an otherwise clear platform, they'll go and stand near you. At the movies, clear-ish cinema, let's go sit RIGHT BEHIND, or even within a few seats distance of the person/people just trying to watch a film comfortably, these fools even do the same shit at restaurants. You annoying assholes.

People who stand in stupid places to make decisions and/or have a chat. This applies mainly to old people, but there are an increasing amount of younger dullards that do this shit as well - lets chat about where we should go next, on the top/bottom of an escalator, lets line up and talk (anyplace) just to overcrowd the lines...etc..send one person and step the fuck off, STUPID.
Same kind of dumbasses are the ones that think it's a good idea to stop with a full trolley directly beside another one in a supermarket isle - completely oblivious, self centred mongos.

Asian chicks (I don't even feel this is a generalisation, seriously, nobody else does this NEARLY as much) with an overabundance of shiny, sparkling and jingly crap hanging off anything they're carrying or wearing...this is annoying.

People with loud shoes. Mainly chicks but a lot of guys have them too...clop clop clop...so many I have seen and wondered how this does not bother the person wearing the shoes, let alone those around them.

People who step into any kind of public transport right after smoking, even worse, those few "moneysavers" that actualy go ahead and snub out cigs before they do, carrying the remainder with them - to both parties here - do not sit near people, because quite often you fucking stink. A simple breath-mint would fix this in most cases. I mean shit, a workplace can bring you up on bullshit like this as a hygeine issue - it applies everywhere else too.
That's not even TOUCHING the assholes who stand there waiting to get off a bus or train, cig in hand like pathetic junkies (well, it is a drug...) then light up the second they get off making all those behind them have to breathe in a concentrated hit...this kind of utter disrespect is a punch in the face-worthy offence, straight up, it's an asshole act.
Parts of some countries have actually banned public smoking (India was the last one to do it that I heard about) I can only hope others get in line.

People who want to split cabs, and cabbies who want to let them, and then both attempted ride-cramper and cabbie alike that act like you're the asshole for simply excersizing your right to ride alone...

Sales people that approach you within the first 5 minutes of browsing a store (electronics stores especially) and even when you tell them you don't need assistance, still "check in" like every second minute. This just makes me leave.

People that use alcohol, and demonize weed - as though they're not the ones indulging regularly in one of the substances responsible for more deaths and asshole behaviour than any other.

Crowds, of any kind.