They may be louder and talk and laugh more, but since their judgement is impaired they may also take more risks, do dangerous things, and be more hostile. If you think you've had too much to drink, eat something. If you think you've had too much to drink, you probably have. The best thing to do is to stop drinking. Eating something substantial may help, and drinking alcohol-free beverages is a good idea but only time will help you sober up.
Coffee helps sober up someone who has had too much to drink.
Coffee is about as good as a cold shower or a long walk. In fact, nothing helps sober up a person except time, or not drinking at all. But then, they wouldn't need to sober up if they had not been drinking. Even though alcohol is a drug, you cannot overdose on it. When you drink too much, that's the same thing as overdosing on alcohol.