Personally I think affective empathy is extremely common, but we just construct strategies to avoid experiencing it too much. Most people are going to experience some level of suffering if they directly witness another person suffering. It's just that no one likes that feeling of suffering so we say smth like "that's too bad but there is nothing i can do here" so we can feel better and move on with our lives. This is I guess what we call sympathy, but really I feel it's just a strategy to reduce the impact of the empathy reflex most of us feel. Imagine what your life would be like if you couldn't get over the feeling you get when you witness someone else suffering - you would constantly be suffering yourself and be totally useless to yourself and others. Strong feelings of empathy aren't necessarily a good thing.

Compassion would be what I think is the difficult thing. Whether you fully understand what someone else is going through or not, you have an intention to help them feel better. To actually act in a compassionate way you need to first feel that others are deserving of your compassion and that can be a very tough thing to develop for anyone but those who are the very closest to you.

> People always confuse sympathy with empathy.

One side of this is just shifting of meaning over time. As this article points out, Adam Smith's Theory of Moral Sentiments (1759) gives the term "sympathy" a very central role, but his meaning is much closer to what we now call empathy.