How do I get emotionally exited?

I'm looking for the steps to emotionally show others exitement in an instance where exitement is applicable. My Dad says I have a problem because I don't show exitement with anything, and that generally I don't really show any emotions. My reasons are because of stress brought on by school and family issues that take up a lot of my time and energy. Clinically I would prescribe myself as being slightly depressed, but mentally sane. I have reasons for my depression, and I don't really show others I'm depressed, I act normal around people, and my friends. I still can have a good time around people, and I act with normal emotions around people EXCEPT when showing exitement. Why is this, and what are the steps to solve the inability to show exitement around people?