Cycling specific things:
Road riding – aside from communting it didn’t appeal, but got into it when covid lockdown happened and was surprised with the fitness gains and ability to ride from my front door.
Gravel bikes – so versatile, got one during lockdown, its great.
Dropper posts – didn’t see the point until I tried one and then never looked back.
Rear suspension – had a couple of full sus bikes that were rubbish, then tried a good one on some proper terrain and never looked back.
Gears – at one point I only had a singlespeed but then 1x came along.