Do you know the reason why you rarely see Steven Spielberg making lengthy appearances in his own (or other people's) movies? Because the man knows, deep down in his heart, that he wasn't born to be an actor - and though Spielberg has occasionally appeared in the odd movie over the course of his career, he's never done it with serious intention. His appearances have been the sum of gags or knowing in-jokes, there to draw purposeful attention to the fact that, hey, it's Steven Spielberg! And in the realms of filmmaking, it's nice to see a director of such power possessing some actual self-awareness. Some directors, however, don't possess the levels of clarity to match. And though there are some filmmakers whose movies have been consistently improved because they decided to be in them (Woody Allen, for example), there are others who fail to recognise on a regular basis that they should not be doing any acting. At all. Take a look at the 10 directors I've assembled here, then, all of whom have somehow managed to convince themselves that they've got what it takes to be actors - non-ironically, I should add. The results have been... well, awkward, to say the least.