It used to be all of them... when I was younger I sucked at games but loved them anyway. Hardly beat any games back then..
Now I'm pretty good at all the games I actually play (don't get me wrong, if I fired up a beat em up or bullet hell game I would suck but I don't enjoy either genre)

Dwarf Fortress of course, but I don't think it's possible to be good at that...

My more recent forays into FPSs (Jedi Outcast) show I'm still not very good at those..

And while I can beat the computer fairly easily in most RTSs I know I wouldn't stand a chance against human players in multiplayer.

I pretty much suck at all games (especially RTS), but I enjoy playing them.

Yes, I have tried some of them (had to use the Lazy Noob Pack, because I couldn't really figure how to implement them myself). My problem with them is that they make the game much more cluttered and confusing to look at than the ASCII version. Suddenly, you have to concern yourself with identifying fairly complex yet small sprites, while the standard version is relatively clean in that regard. The various symbols are simple and direct, making it easier to figure out what's going on.

Also, I prefer it the classic way because, paradoxically, it feels more "immersive" to me, because it seems to inspire my imagination much more than the graphical representations. A lot of the time, the descriptions of characters or objects are much more important to me in these games, while the "graphics" on screen make it clear that they're just approximations of what is supposed to be shown.

Race The Sun.
I'm addicted to a small dose of crashes every other day.

Luckily I found this page which has several DF downloads with the various tileset pre-installed, which made it easy to check out several of them in short order. I don't know about it being cluttered, but I wouldn't be surprised. I didn't really play long enough to notice. What I did notice was the visuals, which immediately put me of. I couldn't agree more with your second paragraph: that's pretty much exactly how I see it :)

Spelunky. (Never played the commercial version, as I prefer the look of the original -- plus, it's quite good enough at kicking my ass without my needing to upgrade.)

These, too.

Rocket League,various rogue lites like FTL or Binding of Isaac.

Well that would be any SimCity game out there,and the thing is,im pretty solid with strategy/sim games..but this one..no

I liked Age of Empires 2 a lot but usually got wiped from the map by my AI enemies. Winning was oh so satisfying...one day my roommate's teenage brother said it was easy. He did everything so fast that I couldn't imagine enjoying it. He said the way to win is to always and constantly be building and never just looking at the screen. I never played it again because I knew it wouldn't be fun racing the clock that frantically.

Exactly the same here. Great game but unforgiving. Man how I hate the ghost...

Then also FTL is excellent but I still can't beat the second level of the Flagship. On Easy mode... Man how I hate these drones...

sega rally
not just the first one all of them
they all kick my ass
sega rally
sega rally 2
sega rally revo
sega rally arcade
sega rally psp

i cant get anywhere with any of them and i have been playing sega rally for 15 bloody years !

i have no idea why they kick my ass so much especially since i play a lot of off road games and usually have little problem with them

Upleveling these skills can be the hardest job sometimes ;)