While I agree validation is important, I disagree that telling someone their feelings are unjustified or that they are being dramatic is the right thing to do for validation.

Validation is about letting the person know their feelings are worthwhile or valid. In my opinion, to practice validation, would be to let the person know you understand. In one of my counseling classes we learned a basic empathy response, "you feel this ___ because ___." It would show the person that you see he/she feels a certain way and state why you think they do, and then allows for the person to clarify and communicate. Validation would open doors for more communication. Like you said, it does much better to help a friend feel better by showing you care and see things from their perspective.