stand in (someone's) shoes
To see or understand things from someone else's position or perspective; to empathize with someone. I used to resent my dad for the placid way he was with our domineering mother, but once I grew up a bit and stood in his shoes for a while, I came to have a greater appreciation for what he must have been going through. If you encounter a bully, try standing in their shoes—they're probably deeply unhappy and redirect that feeling onto others.