I would wager it isn't even noise, but a fusion of all senses, especially your butt :)

I'd say noise plays a major role. I've driven a noisy car for years and now that I'm driving a quiet one I frequently switch a bit too late when I'm distracted.

Sure, all senses contribute, but for me personally, engine noise is the biggest signal (even in well sound-proofed cars).

Ditto. Every car I've owned for over 20 years has been a stick. It's not more work than an automatic at this point and it's not forcing me to pay any more conscious attention to the road.

I can carry a full technical conversation while I heel-toe to rev-match the downshift into second at 60mph so the engine braking bleeds enough speed that as I throw it through the corner into town and lose a bit more momentum I hit the city street at exactly 30mph and can shift back up to third and tap the cruise control and coast to wherever I'm going. I'm not going to test it, but I'm pretty sure I could do it drunk and with one hand.

For me, being stuck in traffic with an automatic is more cognitive load than a stick. I'm always overthinking my inputs..."if I'm extra light on the throttle here, it may stay in gear and not shift since I know I'm stopping in 100m and I don't want constant up/down shifts"

In my truck (automatic), when I'm climbing up to the Eisenhour tunnel, I want it to stay in 4th gear and I'll just give it more throttle, but it won't do that, it thinks it's smarter than me and downshifts to 3rd and I need to hear the engine scream all the way up the mountain. I always try to find the sweet spot for throttle input to keep it from down shifting which means that I'm running about 5mph slower than traffic, and that's annoying.

Since my only inputs are throttle and brake, I'm always trying to find the combination of those to put the transmission in the gear that I want it in rather than just sliding the stick and putting it in the right gear.

Does your automatic not have a way to switch to manual mode?