When I was 14 years old our neighbor put in a swimming pool. Every day I watched the progress, digging the hole pouring cement etc. It being summer I had all day to watch the work progress. Now it came time to install the water slide it was mid August 95 degrees and humid. I watched the worker drill holes for the anchor bolts, the first bolt hole went fine, but the second made no progress. Thinking the bit was dull the worker replaced it, still no joy. Back to the truck, rummage around, and brings back another. This goes on for 20-30 minutes, the guy is sweating like crazy, and cussing a blue streak. As he seats there looking at the hole with No progress, I walk over and ask why is not using left hand drills for the hole. It's over 50 years since that day, but I still recall the look on his face when he realized the drill was in reverse.