The last thing I do before I get on a plane is use the bathroom. I never use their stupid bathrooms but I’ve noticed that as soon as the seatbelt light goes out the line starts forming. Apparently other people just can’t wait to use them.
But then I try to stay away from public bathrooms period. Will only use one if absolutely necessary.
I’m the same. Usually when they start early boarding on Southwest, I’m heading to the bathroom.
I also eat a quick meal just before a flight just in case of a delay, especially long distance.