Effortless and costing nothing, kind words are easily forgotten by the speaker. It was really nothing. Yet to the recipient, these kind words, at the right time and place, can uplift spirits sufficiently to allow them to continue their life, no matter the difficulty. We need more of these kind words, so spread the word.
What does it take to be nice to someone when you could have been equally harsh? At times words that correct bad actions are needed, and in the end will greatly benefit the receiver. They may not like it at the time, but hopefully they will appreciate the time and effort it took you in order for them to improve.