I'm not even a fan of handheld gaming, but mobile gaming pretty much just takes what I dislike about handheld gaming and takes it even further.

Small screen, have to either constantly look down at the screen, slowly abusing my neck, or constantly hold the screen up to face-level. Controls are made for miniature hands and tend to not work well at all with movement, which is a big thing in most of the games I play, and never mind 3D, because then you have to move and control the camera at the same time, which..good luck ever accomplishing that properly with touch screen controls.

Beyond that, most mobile games that aren't ports of console/PC games are freemium games with no focus on the story whatsoever, also not a fan of that.

Only mobile game I ever played quite a bit was Puzzle & Dragons, which thankfully is relatively playable without spending money on microtransactions, and since it's a match 3 type game, touch screen controls were fine for it.