I’ve never worn these but I can definitely see why they’d be uncomfortable. I do have a pair of thigh highs that have a paw pattern on them but it’s just colored/printed it’s not actually a raised/stuffed part like it is on the one in the picture. Also the ones I have are thicker, I don’t like the really thin ones that much.

Are the pads on the bottom like some sort of rubber or hard plastic?

Yeah, they look cute but just looking at them makes my feet uncomfortable. They’re probably only comfortable if you walk on tip toes, but human feet aren’t designed for that.