I'm kind of an irritable person, so I can think of many. Here are a few: (sorry if some of these have been used already.)
It annoys me the most that people think Christians don't have a right to their beliefs, or that their beliefs equal hate.
When someone doesn't give credit to something I say, and then someone else says the same thing, and they then have the nerve to listen to it and think it's then a good idea (because someone besides me said it). This also goes for if I suggest a movie, song, or book to someone, and they're indifferent about it, then someone else suggests the same thing to them and they suddenly decide to check it out.
When someone interrupts me.
When someone purposely ignores me.
When I'm excited to tell someone something, and then they just give me a quick nod and a "Yeah." or "Oh, that's nice." and then change the conversation back around to something about them/their interests, like what I said doesn't matter.
When I have to keep repeating things to people.
When my brother says stupid things that doesn't make sense or makes noises instead of talking like a regular person.
When my mom tells me the same stories about her childhood/teen-age years several times a week. (She is not senile, she's just bored).
On that same note, when my mom refuses to watch something on television I pick out (Dr. Who comes to mind), and instead wants to watch the same lifetime/chiller/syfy low-budget movie that she's already seen three times, or an episode of vampire diaries or smallville that she's seen like five times already.
When people don't throw their trash away after eating something that comes in a wrapper/has a stick.
When my produce goes bad before I can use it.
When people litter.
Chat speak. I have a 16-something year-old-cousin that I had to block her news feed on facebook, because it's so irritating. I'll give you an example. This will actually be taken from her wall, and this is how she writes ALL THE TIME. ::drum roll::
"Juss bc yal hung out all day yesterday doesnt mean he like yuu ." Grrrrrrr.
People who have bass in their car, and insist on driving by my house at all hours of the night while I'm trying to go to bed.
People who sit near me after just smoking a cigarette or applying an entire bottle of perfume to themselves in church.
Smoking in general annoys me, though, because I'm very sensitive to smoke. It clogs my nose up and makes a pressure in my nasal passage that really hurts.
When people use the wrong word in sentences, or are too lazy to say all the syllables in a word. My mom is a good example of this. She uses the word "sarcasm" instead of "sarcastic", and she is also one of those "libary" people. I have given up correcting her, because it annoys her badly, so I just keep my irritation to myself.
People who misspell words on the internet when there's spellcheckers and google to correct it ... not to mention something called a dictionary (watch me now misspell something lol).
People who just plow over helpless animals with their stupid vehicles. Grrrr.
I absolutely agree. My mom has fibromalgia and refuses to exercise, because of her debilitating pain. I have suggested light stretching many times to her, but without trying it, she already tells me that it won't work or that it will make her pain worse. I have pain too. I had a neck injury when I was younger that has turned into a perpetual stiff pain, and stretching really does help me. I was just trying to help, but like another thing I pointed out in my post already, she never credits anything I say. Now if Dr. Oz said it on tv, maybe she would consider it. ::rolls eyes::
PEOPLE WHO FOLD PAPER! Ugggggghhhh! I absolute HATE that noise. It makes my skin crawl.
But if I tell people then they think it's funny to do it even more, so I have to keep it to myself. My mother and husband even do it on purpose once in a while.
I'm not a big fan of cursing, though I admit to saying my share when I get mad or upset (which is something I'm not proud of and am trying to stop), but it really annoys me when people use F words or worse, G-D words, in casual conversations. OR when there's way too much cursing in movies or shows. I'm probably alone on this one, but it drives me up the wall.
When my mom becomes annoyed by my singing, but can tolerate my brother's incessant noise-making.
There's probably more, but I already look pretty irritable, so I'm going to stop there. lol.