Flannel-loving starlet Mary-Kate Olsen was in no condition to be on David Letterman's Late Show last night. Her excuse for her disjointed, unenthusiastic interview? She was "so tired" after her long trip (on an airplane, of course, not via any illegal drugs or booze or whatnot). Letterman could hardly have sounded less impressed with this, and twice referred back to how sorry he was about Olsen being "tired," by which he meant that she never should have plopped down on his damned couch if she was exhausted. Having been in show business since she was six-months old, MKO should have realized she was breaking the implicit talk-show contract: free publicity in exchange for a little coherent dish. If you're tired, buy a venti half-and-half latte to pull yourself together, or relinquish your camera time. At least Olsen shared some bitchy history on Spencer Pratt from The Hills. Clip of that and her tired-ness after the jump.