Spatial awareness, or lack of it. People who walk along glued to their phone - Other people are walking towards you, look up please, don't put the onus on others to dodge you.
People who think notices don't apply to them, such as "please remove all your items" changing cublice at gym/health club, thinking they can save it for when they've finished whatever, they deserve all their stuff getting dumped on a bench. Lockers are there for a reason!
Again at the gym people who use their phones on treadmill so one is forced to listen to conversation, people who think they can reserve a piece of equipment because they've put a water bottle on it, but have walked away from said equipment and then jump at you if you have the cheek to try and use it,having not seen the water bottle, with a "I'm on that" 
when clearly they aren't.
People who set up their office on trains using adjacent seat for stuff and then go into a major hurrumphing session if you ask to sit down in that space. Do they buy two tickets? I think not 
People who park unncessarily close to car in carkparks with designated spaces. On a couple of occasions couldn't open my door and had to access it from passenger side, climbing over gears etc to get to driver seat, not that easy anymore 
Mothers with pushchairs who don't acknowledge with a thanks if you hold the door open for them. I was grateful when I had mine in a pushchair and someone did that for me, the world's a nicer place with manners. Most do, but I remember holding the door for one young mother and she waltzed passed me without a smile, "thank you is the word you are searching for" said I, "I don't have to thank you" she replied "I don't have to hold the door open for you" I responded 
Litter droppers or on a larger scale dumping really big items.
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