yer kidding me ain't ya?!
yer is kinda earthy looking, just like using the word ain't. i know it's wrong, but sometimes use it anyway. yknow.
sometimes i purposedly misuse don't & doesn't & other verbs/words.
& for ppl who've never figured out the difference betwixt your & you're, using yer is a perfect solution to hide their ignorance, but i'm betting at least half of the ppl who use yer know the correct way to use your & you're.