My raiding days haven't been that long. About 2 weeks in fact, which is less than a month of weekly raiding in Karazhan. As a result I've learned quickly there things I dislike about Raiding.
1. Raid not starting on time and people not logged on as they say they would and everywhere else but at the raid location. We've had this happen allot! I myself usually say if I'm going to be late before the raid time is planned because I know I have a long commute time from work.
2. People not using consumables that they know they need to use. I've seen that too which cost us a few close kills and then wasted time having to rez. However more people are using consumables the more we raid so getting better at it and using Flasks but not but at least half the raid don't as yet for whatever reason.
3. Raid members being constantly AFK between pulls or downtime and not saying going AFK and going AFK for long periods of time for whatever reason not obvious. Seen some people gone AFK for like 10 min thus result in everyone having to wait around doing nothing just waiting. One person went AFK so long it we canceled the raid due to no replacement for the AFK person.
4. Raid wasting lots of time to replace members who have to leave or leave suddenly and then have to spend a hour or more to get a replacement. Time is damn valuable my time or your time and it a waste to have it wasted especially with consumables like Flasks ticking away. At least half the Flasks I use go wasted and that expensive.
5. Raid members not having their gear fully repaired. That's just a no brainer! But we have had that happen that I have seen people forgetting to repair. Fortunately myself and others now have enough reps that I can repair inside Kara with Violet Eye reps.
6. I've seen raid members forgetting to bring reagents and forgetting they need then. Seen a pally healer without reagent in the raid and wondering why he could only cast regular blessings. Had to give him one on my stack of 200 reagents. I carry that many all the time in raid and heroics.
7. Sometimes loot rules are not always fair, however the rules are the rules and can still be dislikes all the same even if its the official rules. Oh Well.
8. No set raid time duration. However that said because we can't seem to start raid times on time and often late this have impacted when we end as well. But a set time would be nice. As for me I often have to get up at 0430 to get ready for work and my commute. We've had raids where it was 0200 am when it was just finishing. However I stayed to finish that nights raid, however its not something I wish to repeat often considering my work schedule that are 12 hour days long with commute time.
9. I'll have to be honest on this one. I do have a general dislike of carrying people through a raid who don't take the time to gear themselves to some degree after they hit lvl 70 and think that hey I just hit 70 my gear is not raiding level ready gear but I want to join the raid. Honestly I have a general dislike about that when some people don't take the time to run 5 man instances during the day or off raid time to improve their gear chances but only wait till raid time to get into a raid to do so. If you ask me why that bothers me, well you have never read here for long.
10. Raid members not knowing raid strategy of boss ahead of time thus having to spend lots of time to explain boss strategy. Thats a loss in momentum and that's also time wasted. Only a few people in the raids I've been on seem to do homework on any bosses ahead of time. Can waste a lot of time.