Great idea! My contribution below.... I was wondering if we might need to start a thread on 'personal worst' tank, ha.
My worst was 3-27-19. It was 51.35 mpg, my third tankful that included mostly highway speeds and wet roads. For "in town" driving, what I usually do, my worst was 1-8-21 at 63.4 mpg. Which was confirmed 2-26-21 with 63.86 mpg. Lots of driving on wet roads was the major culprit.