Why is this the answer?

The answer is alcohol because this clever riddle describes something that can affect grown-ups in different ways, using tricky word pictures. It is a puzzle that uses figurative language, which means the words don't always mean exactly what they say. Think about the first clue: "Today he is there to trip you up." This clue has two meanings. First, when some grown-ups drink a little too much alcohol, it can make them feel wobbly. They might lose their balance and actually trip or stumble, like falling over. Second, it can make them forget their good sense. They might say or do things they regret later, which is another way to be "tripped up" in their actions. This clue shows the immediate, confusing effect the substance can have. Next, the riddle says, "And he will torture you tomorrow." This clue points directly to the bad feelings that often come after drinking too much. When a person drinks too much, the next day they often feel sick, maybe with a big headache or an upset stomach. People call this difficult feeling a hangover. The riddle uses the strong word "torture" to describe this small punishment or bad feeling for overdoing it the night before. This shows the long-lasting, next-day effect. Finally, we have the last clue: "Yet he is also there to ease the pain, when you are lost in grief and sorrow." This part explains why people sometimes use this substance. The word "ease" means to make something less difficult or painful. Sometimes, grown-ups who are feeling very sad, worried, or in physical pain might have a small amount of alcohol hoping it will help them feel a little better or forget their troubles for a short time. Alcohol can change how a person feels, but only for a little while. This is why the riddle uses the word "ease" and talks about sadness. It is a very grown-up puzzle that uses a lot of different feelings and actions that one single substance can cause. The riddle is a smart word game because it describes both the immediate and the delayed consequences of this common liquid.