As for my worst game expieriences, some of those were connected to my current notebooks keyboard not being exactly built for gaming: Key Ghosting!
Sometimes games require you to press a combination of three (or more) buttons. Bad luck, if there is a ghosting effect on that combination.
Playing Cave Story+ (which I consider, by all means, a great retro-style game), I find that I can't shoot/jump upwards or downwards while using the cursor keys for movement: No matter what keys I assigned for shooting, pressing a combination of [Up]/[Down] with (depending on the keys assigned for shooting/jumping) [Left] or [Right], there would always occur ghosting on my keyboard (which otherwise is just great). I tried WASD controls (which solves the problem), but somehow it felt so artificial to me, that I would run into every trap.
As for WASD-controls: Actually I felt those to be the most "natural" controls I ever used, combined with the mouse based turning of direction of looking, i.e. holding the right button turning the controls into those of a modern first person shooter, including reassigning the keys for "turning" to "strafing", while the mouse button is pressed:
* while not using the mouse to rotate, "turning"
is the main purpose of my using of they
* while using the mouse to rotate, "turning" with
keys turns pointless, but strafing is still
As [A],[D] are reached with less strain to my fingers than [Q],[E], this temporary reassignment perfectly makes sense for me.
As for Arcanum: It took me several evenings to get out of the first town, because I just the character editor so much Anyway, I found the game generally interesting, except for repairing turning into something genuinly annoying once for the companions, as I found no way to repair their equipment without first undressing them (whereas my own equipment could be repaired directly, without any undressing and shifting items around inventories). A flaw which, by the way, seems to be shared by "Fallout: New Vegas" at least.