Different people handle alcohol differently.
One of the quickest ways to end up drinking past your healthy limit is to try to keep up with everyone else. Men and people with a larger body mass can generally drink much more than those that are smaller than them without getting as intoxicated. It’s an unfair but very real and non-negotiable truth. Moreover, certain health conditions and/or medications can also affect the way alcohol impacts your body. Responsibility.org has an awesome tool (as well as an app) called The Virtual Bar that allows you to estimate your potential blood alcohol content based on factors like your age, height, weight, gender, type of drink, and whether you've had anything to eat.
Not all drinks are created equally. Some will impact you more than others.
It matters not just how much you drink but what you drink too. Different drinks have different AVBs, or alcohol by volume — which measures the percentage of how much alcohol (ethanol) is present in a given volume of a beverage. Wine usually ends up somewhere around the 11.6 percent mark, a stark comparison to beer’s only 4.5 percent average, though, of course, nothing is as strong as liquor, which usually hovers around 37 percent.
It’s also important to keep in mind that darker-colored alcohols tend to contain more impurities and are thus more likely to leave you with a hangover the next day. Additionally, be wary of mixed drinks or drinks, including caffeine. These can mask the taste and even the effects of alcohol, causing many to accidentally overindulge.