I have always conceptualized the notion that "life is short." Given that life spans hundreds of thousands of years and the pyramids were constructed thousands of years ago, my short 80 or so years of life is nothing. It's a blip in the timeline of life and the universe. But I have noted now is that conceptualizing my finiteness is different than internalizing my finiteness. That probably sounds a bit confusing, so I'll elaborate.
Conceptualizing is knowing something without truly feeling it. Now I feel my finiteness. I feel my existence slowly proceeding towards death. Each day is one moment closer to my demise. I could live until 80 years of age..or I could get cancer or have a heart attack and die. You never know. When I was 18 and later 21, I didn't feel this way. So with this realization, I am convinced that I need to spend life being happy. I want to do what makes me feel good and what feels right.
People, including myself, do too many things that don't "feel" right. That feeling is your instinct. That is God and the universe talking to you. But we don't listen to them. We ignore this voice and then are surprised when things don't unfold how we imagined. Since life is so ephemeral, I plan on doing more of what feels right as I turn 30. Life is too short to live with regrets.