system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some people get less severe hangovers or no hangover at all?
gpt
Hangovers are mostly a result of dehydration (except for the nausea, which is a typical result to ingesting anything that toxic).

Moral of the story, some people are better at hydrating before/during/after drinking, and some are better at retaining water.  

Of course, certain drinks can help or hurt. Argument's sake, a redbull vodka contains sugar and caffeine, both of which are diuretics and will result in greater water loss and result in a worse hangover. 

If you're trying to avoid a hangover, try to avoid mixed drinks (go for shots/neat/on the rocks), and be sure to hydrate before, during and after. That gatorade before you go to sleep will do wonders.