5. Fix-All Sonic Screwdriver
By now, everyone's already realized that the Sonic Screwdriver is the most obvious cheat tool that a writer has ever had. No doubt it makes great sales in the toy department and, to be fair, a guy as smart as the Doctor would posses some sort of multipurpose gadget. So while the Second Doctor first brought it up as a way to actually unscrew screws, no one really minded when the Third Doctor started using it to open doors and detonate land mines. In the 1980's, producer John Nathan-Turner did away with it just to make life harder for the writers. But the 1996 movie and then Nu-Who inexplicably brought it back. And thus the abuse began. It may be understandable that the Doctor points the Sonic around just to somehow collect data. But when conclusions to otherwise great episodes (like The Power of Three or Flatline) are reduced to "Doctor points Screwdriver, villains bugger off, everyone lives", you can't help but feel cheated. Sometimes, the "non-weapon" can even produce a very green looking sonic force-field (like in The Rings of Akhaten) or, you know, just resurrect a woman while forever entrapping her in a slab of concrete (like in Love & Monsters). There's no arguing here. Moffat is so aware of this that he often makes fun of the tool. The War Doctor had some really funny lines about it in The Day of the Doctor while in the more recent Death in Heaven, Clara casually asked the Doctor: "Just point and think, yeah?". Who knows, maybe one day the Doctor will break the fourth wall completely and just heroically demand of his companion: "Set it to plot device!"