Piggybacking off the others, aside from alcohol quantity it can also depend on what type of alcohol you drink and in what order. Also depends on how much water you drank, if you ate anything the night before, or if you threw up the night before/next morning. If I get really drunk, I always make sure to drink a ton of water and eat something before bed. Pedialyte is also a great hangover cure. If I know I'm going to throw up, instead of miserably waiting to upchuck I just make myself throw up so I can sleep it off.
Other than nausea/vomiting, other hangover symptoms include: dizziness, light headedness, sensitivity to light and sound, headache, fatigue/weakness, shakiness, difficulty concentrating, increased heartbeat, and mood disturbances (hence why many medications such as antidepressants it mood stabilizers warn against drinking).
Anyway the bottom line to stay safe is to know your limits, drink water and snack while drinking, don't drink too much too fast, don't drink and drive (even a bike!), and never drink alone!

I thought I was going to hate Liam but I love the relationship he and Wooyoung have(づ ̄ ³ ̄)づ
Also, a quick question. I have never drank so I don't know much about hang overs. But when you have one, do you have a hard time eating it in the morning? Just like how it's happening here?