*I think Dave's just way less at ease on camera than any of the others, and it comes across as intense competititiveness and gritted teeth, whereas I suspect he's just not a natural at being filmed. Really, if you think about it, it's far odder that many of the others, without any TV experience, are quipping away and being funny or drinking tea or helping one another out or not snapping at the presenters to sod off while they're trying to temper chocolate or make mango curd, with a camera permanently on them in a stressful situation.
But that's why they screen test the final twenty or so candidates in the tent before they make the ultimate selection -- they're selecting the final cut for ease and naturalness on camera, as well as getting a mix of men and women, ages and races etc.
Which does make sense. I bake well, but this is a feel-good programme, and the viewing public absolutely does not want to see my natural resting bitch face, not to mention the way I glower when I concentrate. I'm a perfectly pleasant person, but absolutely certain I would come across on camera as a grumpy, ultra-competitive hate figure, and spawned a thousand grumpy GIFs*
Yes I guess you're right, I'm always impressed how they can have a conversation with the presenters (and Pru and Paul) when they're making something really stressful, or not get flustered when either of the judges question their ideas or flavours. I'm sure I would end up mucking something up, dropping something or getting stressed out. It just end up mute and not be able to answer any questions!