Well when I got KoTOR I was about 10 years old, so I didn't understand much of the RPG mechanics (skills, buffs, that kind of stuff). But someday I was walking around some games store and I saw that Star Wars game, I didn't know it but it was Star Wars so I had to have it. I was kind of lost when I realized it took place thousands of years before the movies. "Wtf swords in a Star Wars game ?", "Isn't there supposed to be only 2 Sith dudes ? Why are there so many of them ?!" or "Why do the jedi robes look like some kind of ninja outfit ?" were some of the questions I had when I first played it.
The first time I finished it was only years later : the underwater part on Manaan scared me so much (I always were scared of sharks). I actually got TSL first before finishing K1. And that Peragus level was (and still is) so creepy that I couldn't play it at night.
Ah, the memories.