first time I took my eldest son to the High Sierra he was about 13. We headed for Bishop Pass on a beautiful clear day and it was still clear as we headed up the final headwall, but by the time we made it to the pass we had lightning and grape size hail. I had been trying not to push him too hard but no choice once the lightning started. He's never been backpacking again (although he patrolled at Squaw a couple of years and doesn't seem to mind nasty weather any more.) The next year I took my younger son, same place, exact same scenario. He and I have managed yearly trips since then, until med school got in the way.
I was hiking around Castle and Basin Pks when I got caught in a thunderstorm with big hail as I rounded the Saddle at the north end of basin. A couple had taken shelter under a very tall, very isolated tree on the ridge. I chose to crawl under a log instead.
In the Wind Rivers I was on Mt Mitchell watching lightning strike at the far end of the cirque and then the next peak, and the next, and the next, moving towards us. We ran down like we were Ueli Steck or something. Another time we were having lunch on Pinnacle Ridge, near Gannett on a beautiful sunny day after a technical, roped climb when are metal started buzzing. Turned around to see an enormous thunderhead. We didn't bother with ropes on the way down. On another trip we we were stuck on Wolf's Head ridge behind some off route climbers when lightning and hail started at 10AM.
Too many close calls with lightning. I think it frightens me more than anything in the mountains.