Slightly different, but my personal bugbear is the car queue to get on to the ferry to the Isle of Wight, (Red Funnel).
If you are a responsible driver and do what it says on the ticket then you'll arrive 30 minutes early and get placed in a lane ready to board the ferry. They board strictly on a first come first on basis.
First cars on go on to the upper decks until those decks are full, then the lower deck, (used for lorries, coaches and overheight vehicles), is used. Trouble is, at the other end the lower deck is emptied first, whilst the upper deck waits up to 15 minutes to leave, with the very first cars loaded being the very last to leave. When going to the island this also means that you are now stuck in a huge long line of traffic behind the lorries, caravans, coaches etc. for miles.
As I'm a regular traveler over to the island I now wait outside the terminal and arrive 5 or 6 minutes before departure time, by which time the upper deck is full and they put you on the lower deck, sometimes down the middle and straight up to the front, meaning you can be first or 2nd off. It makes a huge difference to arrival time at my Mums and that lovely end of journey cuppa.
I've complained about it many times but they haven't changed the system so I'll continue my tactics, despite knowing it's a bit naughty.