#3 Not putting the seat down on the toilet
Haha!! I know this sounds kind of ridiculous, but it takes about 2 extra seconds to put the seat down!!
#2 Leaving dishes in the sink
I don't understand when people will sit their dishes in the sink, when the dishwasher is literally right next to the sink. It takes maybe 10 more seconds to put them in the dishwasher.
#1 Not using your blinker
Use your dang blinker!!!! It drives me insane when I'm driving behind someone and I have to slam on my brakes because they are turning and didn't let me know by using their blinker. That thing next to your steering wheel does have a purpose...it's not there for decoration!!