Let's start with beer. The taste of ethanol aside (more on this below), it is very bitter. Yuck.
Then there is wine. Sourness in drinks is something I am generally OK with, but in combination of ethanol? Yuck.
I never tried anything else before. Presumably it's equally bad.
Ultimately, it's the ethanol. It stings my mouth and my tongue; once it is in my mouth I find it incredibly difficult to get it down my throat. Often I have to mix my drink with apple juice or milk in order to finish it.
However, despite difficulties on every occasion I still try to drink some when I have the chance. Why? Because I am absolutely dumbfounded at why the heck this thing is so popular throughout the world.