Just two months after stepping down as the host of CBS’s Late Show, David Letterman reemerged on Friday night in a surprise appearance at a performance by friends Martin Short and Steve Martin in San Antonio. Letterman said he was perfectly satisfied with his decision to retire, “And then a couple of days ago, Donald Trump said he was running for president. I have made the biggest mistake of my life, ladies and gentlemen.†He managed to get a few pent-up Trump jokes out of his system by delivering a Top 10 list titled “Interesting Facts About Donald Trump.†If former late-night hosts can’t stay off the stage when Trump launches a presidential bid that’s almost guaranteed to fail, just imagine what they’ll do if Bill Clinton actually becomes the First Gentleman.