OK I haven't read through this whole thread (it's huge) so some of these may grate on other people's nerves too. So be it:
-I very unreasonably dislike it when waiters / waitresses come very cheerfully to the table, when you're (inevitably) in the middle of a serious discussion, and ask 'is everything ok?' First, it's highly unlikely that the answer will be anything other than 'everything's fine'. If it weren't, one would probably have said so to the waiter already. Second, sometimes you have to say 'everything's fine' with mouth full (extremely annoying). Third, it's not great to be interrupted mid-conversation. And to be honest, what's the point?
-I get irritated (fairly unreasonably, I know) when I'm speaking to a friend on the phone & they start having long chats to their offspring mid-conversation
-I dislike it when young children answer the phone. But sometimes (as I know from bitter experience) you can't stop them...
-I unreasonably dislike it when people chew gum.
-I hate it when people sit on the outside seat on the bus, when there's no one sitting on the inside. Why don't they bloody sit on the inside (window) seat & make it easier for whoever comes in after them to sit? (not so unreasonable this).
-I get irritated & disgusted with anyone drinking milk or- even worse- yoghurty drinks, particularly from a bottle (yuk yuk yuk).
-I very unreasonably dislike cats 
. Always have.
-I hate all expressions that are something like 'plonk on the table' 'pop in the oven' 'bung (in the oven again)', 'fling on the stove'. As much as I like Nigella, she does it an awful lot.
-I hate hate hate the words: 'faby' 'rellies' 'Maccas' 'defo' 'chrimbo' (and any word in this category).
And....deep breath!!!