I do find it difficult to wake up earlier than usual - whether it’s half an hour earlier or two hours earlier. And for that reason, I don’t agree to plans that require me to wake up that early and be able to function - I might possibly take a flight that requires me to wake up two hours early, but only if I don’t need to function as soon as I arrive because chances are if I have to wake up at 4 am I didn’t really sleep at all.
I couldn’t time myself and take a shorter shower - but there are two reasons for that. One is because I can’t accurately tell how much time has passed while I’m in the shower. But the other reason is because I don’t take 40 minute showers in the first place. I think I remember reading that the average shower is about 10 minutes, and I guess mine are 10-15 minutes. But whether they are 8 minutes or 15, they take the minimum amount of time possible to wash and rinse my hair and soap and rinse my body. And that’s how someone who normally takes a 40 minute shower can cut their time in the shower in half without actually knowing how much time has passed. Or skip it entirely - which is what I would have to do, since my showers already take the minimum time possible.
I don’t know you or anyone else in this thread ,and therefore I am only speaking about the chronically late people I know - but none of them have had any TBIs or any other medical reasons that cause them to be late. They are late because of things that are totally within their control. My husband used to always be late because he didn’t want to wait for anyone, so he would wait until the kids and I were ready to walk out the door to start getting ready himself. He got mostly cured of that after a time where his sister wanted to meet for dinner at 8 and everyone else wanted to meet at 6 - so she agreed to 6 but went about her day as if we had agreed to meet at 8 and was surprised that we left when we found out at 6 that she was at home waiting for everyone to shower after a day at the beach. There are people at my job who arrive 30 minutes late for a meeting or training who clearly stopped to pick up breakfast when they were already late - not caring that the start of the meeting/training was delayed at least 15 minutes waiting for the latecomers.
Perhaps the worst instance was a group bowling trip - someone ( I’ll call him Jimmy) who was to go on the trip started calling two days before the trip looking for a ride. Sam, who really didn’t know Jimmy well agreed to give Jimmy and his girlfriend a ride. When Sam arrived at the agreed-upon time, his phone call to Jimmy woke the two of them up. OK, everyone oversleeps, and if they had gotten dressed and come down in 15 minutes , everything would have been fine since wasn’t any set time that they had to arrive at the hotel that day. But they hadn’t packed yet and they needed showers and Sam didn’t feel like he could just leave because if Jimmy didn’t arrive his teams would be short a bowler. So an hour and a half after Sam arrived, they were finally on their way. They may not have been able to control oversleeping - but they certainly did control their decision not to pack until that morning and their decision not to skip the showers while someone was waiting downstairs in a car. ( and they certainly could have showered when they got to the hotel). The next year, Jimmy didn’t understand why no one would give him a ride.
If you’re late constantly and don’t affect anyone else, I’m not sure you’re really late at all. After all, nobody would ever say that someone was late going to the mall by themself or even to meet a group of friends at the beach or to hang out at a bar. (meeting a single person at a bar is different). But if you really can’t keep track of time and have to screw up your entire day to be somewhere at 2 pm, then it seems you shouldn’t make plans to be somewhere at 2 pm unless it’s something that’s important enough to you to be worth screwing up your whole day. Which may mean that you never make plans that involve picking up/being picked up by/meeting other people at a specific time. Because while I won’t get annoyed if you are ten minutes late when one of us is picking up the other to go to the mall , if you’re thirty minutes late, I could have potentially done something other than waiting for you during that thirty minutes.