Look up the "TAS2R bitter taste receptor gene family". It's a fun little group of genes that control how well bitterness is detected.

I am a moderate bitter taster. So I do not like celery (mildly unpleasant flavor) and prefer cucumbers that contain the recessive bi gene that stops the production of cucubitacin in the plant. The ones that contain the bt gene, the skin gets too bitter for me. This gene mostly stops the cucubitacin production in the fruit but not the plant.

Yeah I really don't like celery. Cucumbers are pretty good if they're peeled, but yeah they have a very strong taste to me, and the peel is very bitter

Your celery description seems apt to me, but for me it's much less pungent. It's actually super mild for me, so I don't mind it. I actually quite like celery.