Actually these 3 sub-definitions for paradox appear paradoxal:
[merriam-webster.com]
a : a statement that is seemingly contradictory or opposed to common sense and yet is perhaps true
b : a self-contradictory statement that at first seems true
c : an argument that apparently derives self-contradictory conclusions by valid deduction from acceptable premises
I particularly like the Fermi paradox which also include the Great Filter.
Don't know if this qualifies as a paradox but it's my favorite , "why is there something instead of nothing".
Unfounded causality loops. They fascinate and infuriates me in equal measure when I find them in stories.
The Crocodile Paradox
Keep the kid. See if I care. Ha.
I like the Cretan Barber, because it's simple enough that most bright children can "get" it - watching them think it over for a few moments is always fun. I like the Möbius band fpr the same reason: next time you have children around you, show it to them. Some of them think nothing of it; others look puzzled and are clearly thinking "hang on - that's weird..."
More of a trio. 3 sisters who are all general practitioners have a doctor's office here in rural VA.
They are my favorite tripleDox.
Sorry, not my favorite pardox, but one that I found interesting.. (of course it has to do with infinity issue/s ?) "The infinite hotel paradox"
paradox