Turn signal too early.

I am a zealot when it comes to turn signals. I use them, for every turn, always, including into and out of parking spaces. Communication=safety.
But DO NOT turn on your turn signal early. Honestly it’d be safer to not turn it on at all than to turn it on early. Once you pass the last opportunity to turn before the one you intend to use, then you turn on the signal. Turning it on 2 entrances away from the one you plan to use is telling the guy coming out of one of those spots that it’s safe to pull out in front of you. He doesn’t know your signal actually meant “I’m going to turn. Sometime. But oops, not now!”