Mistakes you only make once

First car was a 71 mustang with a 351c. Just out of high school, and I decided to rebuild the top end. Got it all torn down and new gaskets installed. Fired it up and started driving down the highway. Got to a gas station, pulled in to a pump and engine was still running. Some guy comes over and starts yelling at me to get away from the pump because smoke was coming from under the hood. I pulled forward to a spot away from the pumps and killed it. Popped the hood to find the positive battery cable was too long and had been cut by the spinning alternator fins, and had become welded to the alternator! Easy fix and I was back on my way home.