I was a child of the 70s, and this was the theme that freaked me out. What a creepy idea for a show that was, but what great fun.
One of the top 10 episodes for me. But any time I hear Johnny Mathis singing “Wonderful! Wonderful!” I get a little creeped out…
I third this.
I think what this thread really demonstrates is that theremins are incompatible with children.
I was a child of the 60’s and can remember hiding under the lounge cushions when Dr Who came on.
And if the Daleks were the monster of the week . . . . . well we just won’t go there
-Mitch
Unless they’re feeling good vibrations. Or hangin’ out at the Portland Children’s Museum.
I’m a kid of the 80s. The closing music to the Incredible Hulk scared me. I know it was supposed to be sad, but to me, it was also haunting and eerie in a way that genuinely frightened me.
Nah, it didn’t scare me.
The show itself sometimes did, though. 
Also, am I the only one who wasn’t freaked out by “Home”? (That’s the incestuous family episode y’all are talking about.) It was definitely creepy, but it didn’t actively frighten me. I was more affected by “Irresistible,” the episode where the guy kills women and keeps their fingers and hair as trophies. Shudders
Yup, AYAOTD gave me all kind of chills when I was a kid; so did the X-Files theme, even though I don’t think I watched an episode.
But nothing scared the ever-living hell out of me like the Tales from the Crypt theme. I literally had to run from the room whenever I heard it, and actively avoided going near a TV when I knew it was on. I think it was the creepy laugh and the “host” who looked like a zombie.
The Tales from the Crypt theme wasn’t very memorable for me, but the opening sequence was awesome: the walk-through of the creepy-looking mansion, all the way down into the basement where the Crypt Keeper would pop out of his coffin. Classic!
“Home” was a great episode and, I think, the only X-Files episode to have a TV-MA rating. That part where the kids find the dead baby while playing baseball, where they pull the mom out from under the bed. Blech. That episode was one of the most disturbing of them all. I was about 12 or 13 when that show started so, as mentioned above, I too enjoyed Friday night programming on FOX while my parents and elder siblings went out. I always knew the night was over when Highlander came on.
What really scared the hell out of me as a kid? The New Twilight Zone and that old 80’s show Monsters. I think I was traumatized by that one episode of Monsters, “Holly’s House,” with the evil kid’s show puppet.
It’s actually rather funny. Watch “Home” again. It’s both terribly scary and a comedy at the same time. However, I was definitely scared by it.
I came in to post that the X-Files music was creepy, but the Unsolved Mysteries music disturbed me for a few years, at least. Until I hit my early teens or so.
I was a child of the 60s, and it was the theme to the TV show “Thriller” (hosted by Boris Karloff) that freaked me out. It sounded horrible and terrifying. A number of years ago the show was rebroadcast on the Sci-Fi channel. It turns out the theme is really cheesy, partially a knock-off of the “Psycho” shower scene music.
Speaking of the Psycho shower music, I watched this scene a few years ago during a film music history class. This particular DVD also showed the scene without music as one of the features. Without exception, the students in the class found the unaccompanied version much more frightening. I think part of it is that we’ve become inured of this sort of music, since it has been copied so much in subsequent decades. The thing that really got me about the music-less version was that it was almost completely silent except for the sound of water and her breathing. Now that was freaky.
Back to the OP, I was in college when TXF came out. And, no, I didn’t find the theme music frightening – nor anything else in the show. I got grossed out, sure, but never scared.
This seems like the perfect time for me to resurrect my very first SDMB posting –
It seems to me that the X-Files theme is basically the theme from the Desi Arnaz 1960s sitcom The Mothers in Law slowed down and played “spookily”:
X-Files:
Only now I have YouTube, so I can actually pull them up.
Was anyone scared by The Mothers-in-Law?
Hell yes.
I’m 29 and it’s still creepy.
I was always OK with this one - until they got to the scene the scary-ass clown.
That picture isn’t the best, but the damned thing always seemed to come from nowhere, and even though I knew it was coming every time, I could never look away.
Freak no, creep me out yes (late teens).
Not just the title music, but the entire show. I used to sleep with the lights on after watching an episode.