(Click for bigger.)
I've looked at thousands of Tad's "Indoor Sports" cartoons, and as varied as they are, they all have one consistent theme: Everybody is awful, and everybody is laughing behind everybody else's back.
So it should come as no surprise that Tad would get letters like the one reproduced in the above panel:
Dear Tad –
Why don't you draw an Indoor Sport showing the good side of people instead of roasting them for a weakness or two. There are a lot of good people in the world show us some of them occasionally.
a fan for Indoor Sports
And so, as you can see, Tad proceeded to follow his fan's advice, and produced a cartoon where nothing happens and the characters stand around awkwardly, inanely complimenting each other.
I'm going to go ahead and call this the first "anti-gag" cartoon.