Well said, Mistress Cat

It can absolutely "feel" like mashing when you are trying to get up the hill, but in your lowest gears, its not.

I mash in races - particulalrly in time trials, I am trying to teach myself to spin cause it should be better on my body, but I mash cause at the moment thats faster - big chain ring, big gears, powering along at a relatively slow cadence.

I also mash in races with hills, where I try to get over a hill climb without dropping into low gears so I can increase speed rapidly as I crest and start to descend. Its a grind, but it works.

Headwinds always make me feel like I am mashing - sometimes I am, sometimes I am just trying to go forward in my lowest gear