Read on here that someone met Roger Federer and Rafa Nadal with her DS and Roger Federer was snooty and impatient and not interested. In contrast to Rafa, who apparently crouched down so the DS could talk to him properly, was sweet, and just laughed when the DS told him his favourite player was Djokovic 
Benedict Cumberbatch: an acquaintance met him in a work capacity and said he was rude, although I don't have any further details. But he's one of my top celebrity fantasy shags, so I persist in thinking it was a one-off/a bad day.