After many "idiot" encounters, meaning encounters with people who do unsafe things with firearms, I've learned that the secret to doing the right thing and not fuming about it, and not piling up regrets is SPEED! You say something IMMEDIATELY. In these situations, delay only causes us to feel powerless and resentful. When this older guy pointed a gun at you, you should have immediately but calmly said "don't point that at me." End of issue. You didn't, and thus you got angrier, you fumed, and now you regret that you did nothing.