Staying positive and sticking with only comfortable feelings is not the same thing. Staying positive is how we approach what life hands us. Even when we are feeling down, a positive attitude can help bring us back around.
Emotions come from our thoughts and beliefs. When a situation happens; we have an immediate thought about it. That thought then triggers an emotional response. So, if we can control our thoughts and leanr to handle beliefs that hurt us, we can learn to control our emotions.
For example: I could go to work today feeling good. Then I could find a mound of paperwork waiting for me and think to myself, "Great, this is going to be a crappy day!" That thought then starts to bring me down. If I stick with it, I will continue to feel poorly and it can overtake my response to everything. If I adjust my reaction to that mound of paperwork to something like, "That's a lot of work, but I can handle it with some organization" then my mood is less likely to be negatively affected. It's all how you look at things. If you want to be happy, you have to make the decision not to let things bring you down.
Emotions come and go; they are neither good nor bad: our thinking and our behavior is what can keep us repressed or move us forward. So, yes: stay positive, feel good.