When someone leans her head on your shoulder, he expects a lot from you and with the same dignity, you respond back. It requires lots of patience to deal with circumstances when someone is at receiving end and you want people to understand your situation.
When women share her emotion with a man she expects a person to empathize with her and accordingly react and provide a solution to her. She always tries to explain things much granularly and expects a person to understand to that extent and respond back with a positive outlook.
However, in all this, she assumes that the person understood it quite well and that assumption leads to trust on which she relies, and in return, she expects rational and emotional support from him.