I get nasty hangovers from alcohol. The worst aspects for me are probably the dehydration and sleep interruption. The day after a decent bender, I have absolutely no energy or ambition, and then the terrible anxiety sets in. Oh well, it's the price I gotta pay for a good beer buzz, which I do enjoy immensely on occasion.
I also cannot take any kind of cold/sinus medication, because they make me feel like shite for literally two days after taking them. Too bad, cause back in my younger days, I would enjoy a good NyQuil buzz! (Lame, I know...)
Opiate "hangovers" never bother me cause I always make sure I have some to go with coffee and a cig the next morning. That gets me "right" very quickly.