Alcohol : Why do some people drink until they are sick ? Do they know their limits ?!

Alcohol : Why do some people drink until they are sick ? Do they know their limits ?

I'm not saying everyone, and I'm not on about alcoholics.
But why is it that when people go clubbing or to a night in the town, always come home and vomit everywhere ?
Then the next day they sway around, bang into everything in the house, break a load of cups, glasses and plates, then insist they only drank 1 pint.
Yes, I do drink, but I know my limits and I know when to stop so that I won't be sick. Do some people just not know when their limit is ?
Thanks, all opinions, stories and answers welcome, best answer gets 10 points.

Well, most of the time I know my limits and keep them. however, on the few occasions where i have ended up getting sick, one was because my boss, (we were partying at his house, best boss i ever had) had peach schnapps and beer, and since i dont drink beer, he gave me this big glass of schnapps, and teased me for nursing it, because he wasn't gonna let me drive home anyways, my fiance and i were to crash there. So I said okay if im not driving, then i'll get drunk, and chugged an entire like 16oz glass in about 5 mins. so like 16 shots in 5 mins, and i was okay for a while, but when i relaxed on the couch, i got that tired feeling, and laid my head down. that was my mistake, i had the urge and had to run for the bathroom. Mind you, this was like an hour later, and my friend and i were side by side, i had the toilet, he was half passed out between the toilet and the tub. lol the porcelain gods heard us that night.

Another memorable one was when i went to the bar pissed off, had been arguing with my hubby all day, and i wanted to get drunk, and ppl kept buying me drinks, and i think i had like 8 while I was there, which was only about 2 hours, (but this was after not seriously drinking for about 5 years) and threw up at the bar, and had to be carried home. I say carried home because I walked there, since it is like a half block, if that, more like a driveways length up the street, and over two doors, and my two friends literally carried me home, ,but i did try and walk, it just wasn't working very well, and of course i had to stop and vomit in the street as well.

I have a few other funny as hell drunk stories, but those were the only times i drank till i got sick, because i usually handle my liquor really well. Most people i know that make it a habit of drinking till they are sick, don't know their limits, or are so depressed or upset about something they drink and drink till they can't think anymore, and just want to drink they pass out.