When I first started playing Dwarf Fortress, I was bothered to NO end that the only playable civ was dwarven.
I came into this game absolutely hating dwarves.
In fact, the very very first thing I did was learn how to mod humans as a playable civ.
However, after giving in and playing some dwarves, doing a few forts and playing the game, I came to realize that the dwarves in Dwarf Fortress are not the same as regular fantasy dwarves.
They are inquisitive and curious, deadly and intelligent, yet occasionally innocent and naive. They fight like demons and live glorious lives of beer and women and construction and productivity.
They are not just mountain bound bearded half-men. They are a sometimes cute, sometimes horrible and altogether unpredictable race of awesome creatures.
I now love dwarves. You couldn't get me to do anything but kill a dwarf before I played Dwarf Fortress, but now they are my fantasy species of choice, as this game made them a fully three dimensional fleshed out race of creatures which are etched into my mind as vessels of my imagination and hard work, constantly changing and evolving to impress me at every turn, and disappoint and confuse me at every other turn, all the while amusing me in both circumstances.
I used to ask why dwarves. Now I ask, why not?
I love my little dwarfies.