Pet peeve debate: is it ruder to be 10 minutes late or to show up 20 minutes early?
My sister showed up at my door at 6:40 for a 7:00 dinner last Tuesday and just stood there smiling, and now I'm honestly not sure which one bugs me more, so tell me which side you're on.
Sounds like your sister was just really excited to see you, or she has zero concept of how time works. Showing up 20 minutes early is like being the first one at a party and just standing by the chips, awkward for everyone. At least when someone is 10 minutes late you get to keep doing your own thing without a human staring at you from the hallway. 6:40 for a 7:00 dinner means she caught you mid-shower or mid-couch-lying, and now you gotta entertain her. Tardy people steal your time, but early people steal your peace before you even had it. I'd take the late one every single time, no question.