Expanding the Verse has been holding the "Worst Video Ever Challenge" and the results have been interesting.
I think, more than anything, viewing a vid that exploits all the things that essentially make up a bad vid might actually highlight what it is that makes a good vid.
starrylizard has created a fabulously awful vid called 2 Strong Hearts. I love how well observed this vid is in containing all those things that contribute to making a "bad" vid. Read the "warnings" to get an idea of what those things are. :D (I think the "over and over and over" has to be my favourite..)
You also have to check out greyowl88's Fuel. She claims this as the "Worst Wincest Vid Ever". I'd say it's the funniest ever. ;D It's hilarious in it's "badness". (fav might just be the gratuitous crotch shots *g*)
There is actually a thing called a Lord King Bad Vid. I learned of this a few years ago when I voiced the idea of making a Dean/Cas vid to the song "Wind Beneath My Wings" (I'd still love to do this one day...) It's described as: ...the vid your inner twelve-year-old thinks is the best thing ever!" It's about creating a vid that's "bad" but pursued with utter sincerity. The above vids are not quite so subtle in their "badness" so they may not be consider LKB vids. But you get the idea.
I know that fandom sometimes has badfic memes etc. - fic that encapsulates all that is bad in fic writing (such fun!) No reason why vidders can't play with the same.
These vids are also good examples of things to avoid if you are starting out. It's all been done in fun. All vidders have started somewhere and the reason I find these so amusing is because I recognise my own mistakes in these./o\
Enjoy! Or.... err... not. :DD