The song he wrote for The Electric Company (1971), "N'T" has the singer trying to get a grouch to come out of his shell and play. In the end, he succeeds. While a fan may expect a bit of sarcasm from Lehrer, he sounds sincere and supportive the entire song towards his opposite. (Also played by him.)
It's kind of cute that when he comes back out to take a bow after his filmed appearance in Oslo, Norway, he only gives a shy little nod. he almost seems surprised that people would applaud his darkly comic songs. It's also gratifying - the audience was pretty cautious throughout the recording, so it must've come as a surprise to Tom that they actually appreciated his performance.