10. Before Murdering Someone, It's Polite To Buy Them A Drink First
To be fair, nobody can say for certain that the Doctor actually bought the drink that he offered Nice Mr Clockwork Robot. Indeed, it seems far more likely that he just grabbed a bottle of what appears to be whiskey from the selfsame robot's restaurant, so the advice should really be, "Before murdering someone, steal alcohol from them and offer them a drink from that". And if you really want to get specific, viewers aren't really certain that the Doctor actually murdered nice Mr Robot either. The best case scenario that they're presented with is that the Doctor didn't kill him, just convinced him to commit suicide. After convincing him that his deeply held beliefs about the afterlife were all a lie. So let's revise the advise again. "If you are in a confrontation with someone, the best thing to do is steal their booze, get them a little drunk, undermine their entire belief system and then convince them to commit suicide while you watch". There. Sorted. He really is a bastard, isn't he?