David Letterman must have been thinking, “I retired too soon.” With all the material presidential candidate Donald Trump has been serving up, the former Late Show host apparently couldn’t resist coming up with a Top 10 list. Last night in San Antonio, Letterman joined Steve Martin and Martin Short onstage at their show. “Every suit I own comes with a list,” Letterman told the crowd, then proceeded to tick off items making light of, among other things, Trump’s trademark stylin’ hairdo. True to form, Letterman saved the best for last. Or rather No. 1.