It helps me to picture empathy this way. Most days we are all just hanging out and chatting about our lives.
But there are moments in our conversations when you notice that a friend says something unusually personal. In doing so, they go out on a limb emotionally.
When a friend is vulnerable, they need empathy. And that usually requires vulnerability on our part — accessing some sucky memories and feelings we'd rather forget in order to meet them where they are emotionally.
Some limbs are easier to get to. If a friend is going through something you go through often (say, homesickness), then you might know the way to that part of the tree. You can meet them there by thinking about your own sadness, longing for home.
Other times we must go to unfamiliar territory. For instance, you might have to comfort someone going through a breakup when you've never been in a relationship. You might not know the exact feeling, but you probably know sadness, loss, and regret.
The goal isn't to talk about your experience. The goal is to come just a bit closer by thinking quietly about how sucky you felt and thinking about what kind of friend you wanted in that moment.
The hope is that in time, we become more mobile in the tree by understanding our own emotional journeys. As Brené Brown, Ph.D., puts it in her terrific ladder metaphor, empathy requires me to "connect with something in myself."
The more we listen, the more we'll find that even very unfamiliar experiences will have familiar emotional elements. Empathy won't fix the problems. But it lets us be there. Sometimes that's all we can do.