A few kind words to another person can have a huge impact. You never know when a compliment can impact someone's entire day (or their whole life).
It does not take extra time to praise someone or tell them how you admire something they do well. I had a conversation with Stephen Lahey of SmallBusinessTalent.com and he was so genuine and wonderfully caring... that it had an impact on my whole attitude for the rest of the afternoon. .
If you are not familiar with Stephen or his podcast, I highly recommend you listen. He is a very nice man who has a lot of great ideas from small businesss. He has interviewed some great guests, and I always learn something from his show.
Have A Great Day