So let's talk proper dishwasher etiquette. First, and this should seem obvious, you should always have a full load in the dishwasher before starting the thing. Not does it save water to run a full load instead of half a load, but your dishwasher is designed to work best with a full load. Besides, opening the dishwasher after it finishes its cycle only to be greeted with half a load is confusing, even if the dishes are clean. Are the dishes really clean? Why is there half a load in there? More importantly, who on earth decided that running half a load was a good idea? Look, if you need a clean dish that badly, wash it by hand. It's not that hard, and it's pretty meditative once you get into it.
Once you've mastered loading the dishwasher and putting it through its cycles, unload it in a timely manner. There's a reasonable chance you're still using dishes while the dishwasher's running and before you unload the thing, so unloading it quickly means you avoid watching the dishes pile up in the sink with no place to go. I can be guilty of letting the clean dishes wait; I'm the kind of person who will pass through the kitchen and start unloading dishes for two or three minutes, then realize there are more exciting things I could be doing, but it gets done. This is a team effort unless you live alone (in which case it's your fault alone) or there's a designed person to (wo)man the dishwasher. That's not the case in my household, so everyone in my household gets equal blame. Well, except one whose arm is mostly out of commission, but everyone else gets equal blame.
Once the dishwasher's unloaded and ready for new dirty dishes, for the love of all that is holy, put new dirty dishes in the dishwasher and not in the sink. This one irks me more than the other two items combined, and it's all I can do to avoid yelling "WHYYYYYYY?" whenever I see someone else put a dirty dish in the sink and there's a perfectly good dishwasher waiting for those dishes.
Seriously, people, it's not that hard. Next up: laundry etiquette.