For me it was because I wanted to be an astronaut. The cool ships and lasers brought me to the show. The realism was facinating.
Once I started watching, the whole Eqyptian, "what if" thing hit me very hard. I was fascinated by the idea of us having evolved from another world. I had already long believed (at my insanely young age) that we were not alone in the universe. Now I had a new concept to work with. My brain was spinning! I even wrote grade school themes on it.
Regardless of what science tells me now, part of me still believes that it all might have happened. The more I read about the Spinx, the more I have to wonder who really built it.
Am I gulible or is that good story telling? I like to think that it is the story.
BTW - The cute guys in the tight pants did not hurt!