Something REALLY annoying.
If you can say a whole long speech in the space of three seconds, pick your nose and eat it, talk at a barely audible volume, don't notice when people could do with a bit of alone time, won't shut up, are extremely selfish, don't care what other people think and don't notice ANY of the above about yourself then you are an RRGH! person.
If you try and try and try and you can't get this one thing right and everyone expects you to but you can't and people are getting annoyed with you because according to them you should be able to do it then you get an RRGH! feeling.
Ever felt like throwing something across a room. RRGH! feeling. Books that end in cliffhangers always give me an RRGH! feeling.