when you have on the largest position you have ever had on, and unlike everything else in your life which always moves against you, miraculously starts moving in your favor, it is a beautiful thing
Just to give a data point. My largest recent position was INTC which had a very good run over the past couple of years (and it's great when a run like that benefits a portfolio) and I got very uncomfortable as it became about 10% of my portfolio. All of a sudden I found myself obsessing over that position, second-guessing, etc. I finally cut it back to about 5-6% of portfolio so it wouldn't be on my mind so much. I realized I got myself into a position where I wasn't thinking clearly about INTC as an investment, but was focusing on it because of it's size. That type scenario is what I'm trying to learn to better deal with.