Do not turn off Vsync. Just a cautionary tale:
I turned off vsync to try and improve my abysmal FPS in Skyrim, and I had noticed a few minor physics glitches, like opening a door and all the movable objects in the area would fly around, dead sabre cats floating to the heavens, etc, you know, nothing major.
Then I went into a dungeon.
Everything goes smoothly until I see a Skeever in a wall. Yes, IN the wall. I thought to myself "...That's not right." but pressed on anyway. Directly after i passed the wall with the skeever, i came across a long, narrow corridor and proceeded down it. Before I knew what was happening, a GIANT (even in name) Frostbite Spider appears from UNDER THE FLOOR directly in my face. Now, I am completely afraid of spiders, even in video games. So when this happened, I freaked out, fell out of my computer chair and then immediately closed skyrim, enabled vsync, and downloaded every no spider mod on the nexus.
The End

tl;dr: Yes, I've genuinely been scared in Skyrim.