It depends on the situation, if I have important things I absolutely need to do I can pull an allnighter pretty easily and be awake and alert the next day, even stay up all night AGAIN if need be, however 2nd night is not easy or pleasant, it's hard as shit and hell on earth, and the following day is a little better during the morning hours but quickly becomes awful again.
I'll try to explain how it affects me.
The early discomfort symptoms starts setting in during the first night, this includes stuff like shivering and feeling a little depressed but other than that I don't notice a big difference until the day after. This became very obvious once a while ago where I decided to drive(never again) to school after an allnighter and I could immediately feel I lacked the awareness and alertness I usually have when driving.
I also find that in general I have a harder time focusing my vision on anything more than 20 meters away and everything becomes sort of hazy and a little blurry. I also imagine my cognitive capabilities worsen pretty substantially, but I've never tested myself like that.
Thing is though, without something important to do or friends around me I find it nearly impossible to stay up late, I can't pull an allnighter just for the sake of doing it, I'll crumble within a few hours.