In no particular order:
1. People who drive with their foglights on, even in summer
2. People who drive BMWs which are older than 10 years, and think they now own the road
3. A combo of 1 & 2
4. People who constantly say "I tried" or "I looked" or "I was going to" when they are in fact just lying to themselves
5. Chavs walking round with a cigarette behind their ear
6. Chavs in general
7. People who throw litter from cars
8. Shop assistants who have no knowledge of the products in their store
9. People who complain of being broke, but can afford to smoke
10. People who complain in shops/restaurants/public for the sheer hell of it
11. People who shout at their kids in public
12. People who buy dogs just for show (pitbulls, staffys, bulldogs etc.)... possibly related to point 6
13. Lawbreakers who get away with it... see points 14 - 20
14. People who use their mobile phones whilst driving, without a handsfree kit
15. People driving without one or more of tax, insurance, MOT
16. Shoplifters
17. People who lie for financial gain
18. Drink drivers
19. People who abuse their children
20. Vandals, who destroy things for no apparent reason
21. Kids who don't give up their seats on buses or trains for the elderly
22. The elderly who have a chip on their shoulder about being old
23. Waiting in queues of any sort, i.e. doctors, supermarket, traffic
24. Motorists who force you to break hard as they pull out in front of you (when there is a GAP behind you) and subsequently then indicate to turn right moments later
25. People who say "I hate computers" when they have an IT problem which THEY have caused
26. The manufacturers of food or other items who build a flaw into their packaging which stops a quantity of the (usually expensive) item being used: toothpaste, 'atomiser' perfumes, etc.
27. Non-UK callcenters
28. Yellow Pages sales reps
29. Poor quality service in restaurants
30. Telephone calls which are unsolicited
31. Liars
32. People who leave dogs in cars on warm days (No... opening the window a little is NOT good enough)
33. Spam email
34. People who spit in public
35. The disgusting few who do not flush public toilets after use
36. Monopolies who take their customers for granted, i.e. BT, Royal Mail etc.
37. Not being lucky
38. Kids who haven't paid bills, gotten laid—or even grown pubic hair yet—thinking that they know all about life, the universe, and everything
39. As 38, but applicable to adults
40. The price of fuel
41. The lack of taste in UK food, compared with the continent
42. Unadventurous people
43. People who slate something before they've tried it
44. People who aren't good at their jobs
45. Women who are over-aware of their sexual prowess
46. Men who are vain
47. Bullying, of any kind at all
48. Dogpoo on the pavement
49. People who over-obsess about their physical appearance: i.e. 'size 0' women, fake tanners, etc.
50. People who think they have a right to be better than everyone else