People who wave their pints around and dribble beer down your back
People who leave after three songs in a huff (mate, it was the Pet Shop Boys. They were playing Pet Shop Boys songs. What did you expect, and why did it take you ten minutes to extricate yourself from your seat and tread on my toes three times in the process?)
Dodgy security taking back handers from people without tickets leading to deaths from overcrowding and closure of venues
Loudly singing the wrong lyrics, out of tune, during an acoustic number
Massive stadium gigs that finish at 10.30pm meaning half the people trying to leave miss their trains home. Just start a touch earlier, Harry wouldn't mind and he'd probably be happy to be tucked up in bed 30 minutes sooner
People who say they'd like to come to see a gig with you then get huffy because they don't recognise all the songs, even though the last time they listened to the artist was 20 years ago, and since then they've released about eight albums
Excitable social media clips of a tour that looks absolutely amazing and which now - because I am susceptible - I would love to go and see but which will be like the Hunger Games when it comes to trying to get tickets to see in the UK so I will just have to resign myself to waiting for the tour video (do not let me down, Taylor Swift)
All of these taken from my direct experience so far this year.