One of the most frustrating things about mom-dom is having to sit back and watch your kid hurt. Whether it is to help them learn a lesson, or grow a little more independent or just survive one of life's lovely little tragedies, it is what I have hated the most about being a mom. When babies cry, you pick them up and give them a bottle or passie or blankie and most of what is hurting them is gone in two seconds. Then, they are able to put into words what is wrong, and you can talk them through the rough spots.
When they go to college or whatever life takes them to, you are suddenly separated by miles, and you hear their voice over the phone. The anguish and disappointment over the lines breaks your heart, but you KNOW they have to handle it. Although there is not a lot you can do, you'd do whatever if it would just make the pain go away. You know that life will be better and that the days ahead will get better as time passes, but they are dealing with the here and now. And it hurts. All you can do is love them through it. Man, it's hard.