Pre-flight? TSA is a headache, barking instructions at a crowd is annoying, and boy do I appreciate Pre-check. There people are actually experienced travelers, and also have less to do like take out laptops and take off shoes. A big help in keeping us moving.
I hate that we have to get to the gate really early and people start lining up to board first in their group sometimes 30 minutes before boarding. Really? But worse is when the plane arrives late, 200 people are already all lined up for boarding, and the disembarking passengers can't even exit through the gate area because it's so jammed! I know we all have roller bags we don't want to pay to check that we want to get into the overhead space.
Lack of charging. Only newly refurbished airports have enough charging (like should be a USB or plug at every seat!). Everyone now carries a device that not only is a phone, but has their boarding pass and tickets for the train when they arrive on them. Plugs should be everywhere.
Rip-off food. $5 for a bottle of water? I can't take it past security so now you're going to gouge me? Come on. Even the McD or BK has jacked up prices past security.
The lame offers for being bumped. You really think I'll want $100 certificate to be bumped off an overbooked flight? That's rather low. A free ticket, that's what it used to be, and much more reasonable particularly since the next 10 flights are all going to be overbooked as well.
The credit card that gets you priority boarding. I find it amusing that UA now has Group 1, and pre-group 1 (global services), and pre-pre- boarding (uniformed military), and pre-pre-pre boarding (actual slow boarders), all before Group 2 that's for the barely elite and the credit card priority people. That's a lot of levels!
Just how lame United Club lounges are compared to the rest of the world. When I'm at an international airport at a club run by another Star Alliance partner, there is real fresh food, plenty to drink, etc. United has measly pre-packaged cheese, crackers, plus a few soft drinks and coffee, and the new thing is cookies. You have to ask at a bar for the cheapest beer or wine, other drinks you have to pay for. I can actually make a decent on-the-go meal at other lounges worldwide and even enjoy some of the local culture's food. I get to go to the lounges when traveling internationally due to my status, and I can't believe people would bay $500/year for this "privilege".