Here is my thank you to those who quietly helped me by upvoting without leaving comments.
They also have not acknowledged it and I don't expect them to.
I make a point of checking those "silent angels" who upvotes with power but seldom makes much noise.
I imagine that they are much like Santa - lots of places to see and people to go* (intentionally switched).
So, they just leave you a present and never look back and on to the next.
If / when you look at them on steemd.com, you will see clearly that they spend most of their time upvoting and seldom comments with pleasantries.