Are signs really that hard to follow?

Another pet peeve of mine involving other people's driving are people who do not understand how 2 lanes turning in the same direction works. I tried to find the traffic sign designating 2 lanes turning in the same direction but unfortunately I couldn't find one (oddly enough). What bothers me is how people understand that 2 lanes are turning in the same direction but for some reason, feels that the 2 lanes turn into one and end up cutting into the other person's lane. Can people not understand that if there are 2 lanes turning in the same direction that there are 2 lanes all the way through the turn?? It puzzles me how people engage in this turn only to feel they can drive where ever they want, even if it means other people's lanes. People, learn your signs and please follow them, they aren't there just for show.