Life is too short to withhold kind thoughts.
I used to be embarrassed to tell people how I feel about them, even if the sentiment was very positive and I knew that the people would very much appreciate hearing what I had to say. I had a near death experience when I was 17 and realized that it would be horrible if I had died and those things had gone unsaid. I then wrote notes to several of my friends and acquaintances telling them exactly how wonderful I thought they were. Now, whenever I feel shy, I remind myself that life is too short to withhold kind thoughts.