You're doing all the right things - drive in your comfort zone and don't overstep you abilities.
this is one of my pet peeves:
They always seem to take the opportunity to pass but never acknowledge my efforts.
If I was driving on a country road at the speed limit and I see more than 3 or 4 cars stacked up behind me, i USED to pull over at the first opportunity. I did this for years and thought I want being courteous.
However, on a drive across PA last year, I pulled over more than 20 times on a single day and not one driver waved to say "thank you".
Guess what? do you think I pull over any more?
Trucks drivers used to signal a "thank you" by turning on their 4-way blinkers for 2 or 3 seconds - I have not seen this behaviour for a number of years now.
I think I may be becoming a grumpy old man.....