I think we divide in two distinct groups here.
Guys who attach trailers all the time and just don't need any stinking little yellow balls, and guys who attach trailers a few times a year and need all the help they can get.
Before I got my yellow balls, I would phone my truck driver neighbor and he would come over and back my truck perfectly under the hitch. Of course, I was watching and signaling to him.
I used to try to get my wife to help me back it up, but she has a special feminine set of hand signals, which change for every situation.