I've done these same things so many times! It used to make me really upset, now I just have to laugh at myself! My two biggest things I forget are:
I get in my car, get all settled in, start the car, etc. they look around and wonder if I am really even in my own car or if I got into the wrong one! Then I get out and look to make sure it is my own car! I know, sounds so stupid, but I do it ALL the time!
Also, when I take a shower, I always forget if I washed my hair or not so I end up washing it several times before I realized I already did it. At least my hair will be squeeky clean right!
I am a big fan of post it notes. I keep them all over my desk at work. I also put them in my car so I don't forget to pick up my daughter from school. Sad but true!