Feelings: Natural or Forced?

How can you tell the difference from what you want to feel and what you are naturally feeling?
There are so many different circumstances in life. For example, I know I should feel stressed for finals, but I am not. I know that by the time they are about to happen I'll try to stress myself out to be concerned and hopefully study, but I won't really feel that way. Here's another one, anniversaries, after the fifth or so, I don't think I'll care that much. Don't you prove to the person you love them everyday? And don't you sleep next to them almost every night? Isn't that a good good enough reward? So, perhaps, we've molded ourselves into thinking we should celebrate something or be excited to celebrate something when it's naturally celebrated every minute.