If I am chilling at my place i'll drink half a bottle of vodka in a few hours time while watching TV, and feel warm and happy... but not anywhere NEAR sloppy.
Sometimes i'll go out and have 8 - 10 beers and 5 shots and be totally smashed.
I think its alot to do with the environment and alot of other factors. Mindset plays into it a lot too I think.