I have, on several occasions, left hefty sums of money for the wait staff.  I have never waited to see his/her reaction.  Also, I always “overtip” – unless there was gross ineptitude or attitude problem. I try my best to tip in cash, otherwise tips are recorded on their taxes. The government already “charges” them 15% for assumed gratuities. Seems despicable.    
I try to tip people in most professions that have provided me with a service, of any sort.
I am not in a high-bracket income, but every once in a while, people can be nothing but astounding.
People in general are not rewarded enough for just being “them” and delivering quality service, as a “human being.” 
In daily life, I will openly compliment perfect strangers if I find something striking about them.
The world needs more love!