On the eve of the very end of Barack Obama’s presidency, how about we … shove our heads deep in the sand, till grains of gravel are knocking around in our eardrums, and wind back the clock to its beginning? You remember the eve of Obama’s first inauguration, don’t you? When we were all little-engines-that-could and The Late Show With Stephen Colbert was but a faint whisper in the mist? Back then, we had problems, sure, but we also had The Colbert Report and its host, “Stephen Colbert,” and that, well, that was something. Alas, those days are dead, so in lieu of dumping a bucket of mac and cheese in your lap, the real Colbert devoted a segment of Thursday’s Late Show to a blast from the legally kosher near-past, treating viewers to a final Obama farewell by identical twin cousin to “Stephen Colbert,” “Stephen Colbert.” Yet, while the visit did make us ache for no. 44, it also had us hurting for some more “Colbert.” After all, where are we possibly going to find our fill of “truthiness” without him?