I find everything offensive

In no particular order. Also, I love lists!

People who waste paper.
(I originally spoonerized it: People who paste waper.) They just print everything willy-nilly (96 pages) and then are aghast when it all comes spewing out. Furthermore, they just toss what they don't need in the wastepaper basket rather than try to recycle it. They are not the only people who do it, and I see it nearly everyday. It's aggravating. I try to explain to them it's wasteful and they're like, "Oh, it's free." I'll give you something free, too: she's called Bertha and she's shaped like my fist.

People who smoke.
I don't care if it's outside, they are still bothering nonsmokers with their smoke. After all, just because it's outdoors rather than indoors doesn't mean you are not annoying anyone. You know smoke, like, doesn't stay in one place, right? I think people shouldn't walk and smoke. I hate running ahead so I can stay upwind of the smoker so I don't get treated to the fumes. I mean, it's one thing if I know someone is smoking in one spot, but to be enjoying my walk or the weather or something and all of a sudden this gaseous poison just lands on my face ruins everything. It's like someone walked by your restaurant table and decided to just surprise-fart in your face as you were enjoying your meal. There are other things you do (or should) not do in public that doesn't lead to everyone getting up in arms about an encroachment of rights; why not smoking?

People who stand in front of me on the subway.
It's not a crowded train. There are even a couple of seats available. So why are you standing right in front of me? (I'm standing at the door, so I can't move backwards.) Trying to assert your dominance? Claim a spot? Bitch, I ain't moving.

People who are rude.
I can't really list one-by-one individual behaviors that offend me anymore. There are plenty.

People who are close-minded.
Let's say you try to explain to them they are wrong. Like, factually wrong. They do not listen. They can't even accept the fact that they COULD be wrong, so they yell at you. WTF, dude. It makes you looks ignorant AND stupid. And, it's also rude. (And people who are close-minded to opinions too.)

Sexual harassers.
Stfu, stfd & diaf kthxbye

Douchebags, pricks, dicks, and assholes (and jerks).
Yeah.

Everything else.
I'm exaggerating, but I do not have time to list anymore -- I could be here all day! I have to finish reading. (And it's more like, "Almost everything else.")