I said "no" because I don't recall ever forgetting. My service carry was a Hi-Power and I shot a Colt 1911 on a pistol team in the 60's and 70's. That thumb safety has been pretty heavily ingrained in my thinking. Today I have eight active pistols and the oldest was designed in the mid 90's. Only three of these "modern" pistols has a manual safety. [the XD c 45 has a grip safety that I like, but it doesn't count] I still swipe off the safety in my non-so equipped guns before shooting. I guess I haven't been put under enough stress yet.