I think this is a good point. The more aces and service winners you get, the more you can tolerate doubles. My old tennis encyclopedia lists the most double faults in a season going to Michael Stitch. But he finished that year @ #2. I bet his opponents hated knowing that even if he missed his first, he was coming at them again with the second. Anything your opponent hates is good to do. If your serve is just a way to begin a point, then it's different. In that case zero doubles would be your goal.