What are some insults you've made up on your own or have heard from other people?
My dad has: Slap dick Diesel Dick Dick fuck Ass fuck and a bunch more
I have: Fucktard Lametard Turd mouth and more that I can't remember.
Douchenozzle is a personal favourite.
My mum uses "Imbo" for Imbecile. And me and a friend of mine use various ways of saying 'motherfucker' to address each other...for example: "Maternal fornicator". I can't remember the rest...

Yeah, I know :P
I made up a phrase in my school, in about eighth grade: What the crap? And I got made fun of for using it.
Then lo and behold, a year later, everyone's using it, claiming THEY invented it.
Oh, and dicknugget. Dipshit rolls off the tongue too, but it's not original.
I also use dick licker XD
That's why it's such an effective swear word - it is so repulsive to many people :)
I thought of another one...my older brother came up with "Wankstain"...or at least he used it before it became more widespread lol.

^ I say that a lot. Mainly to my brother.
Don't forget the amazing Shit-for-brains
Failbag. Fail + douchebag = failbag.
Omg I need a life. Anyway, I use that for my brother.
Bop - cocksucker (long story) Assbag Dickface
I also use unclefucker a lot because of South Park.
Anusmuffin -- Anus + Muffin. It's like calling someone a piece of shit. Bitchmuffin -- ...I could just use bitch but where would be the fun? Dogfuckingwhoreface -- Only one person gets called this, but she deserves it. (what can I say? My sis-in-law is a whore.)
My brother's friend calls people "poopturds" ????
WHAT'S WRONG WITH CHOO? ahem, basically. xD Sadly, I don't really like to swear people out.
Smote There is a story behind it. XD I found it in a book, the author wrote smote (past tense of smite), and I was reading the prologue to my friend over the phone, and we decided it sounded like an insult. Actually, we thought it sounded more like a racial slur. We both started using it, and some other people actually did too. It made us laugh.
Every day, instead of a simple "hey what's up?" me and my (online)friend greet each other in insults. Here are just the FEW that i remember right now:
turd burglar (one of our favorites...once had a 1 to 2 hour conversation on what EXACTLY a turd burglar was) sac greaseball sleazyass ball licker slum slim skuzz
the list goes on
LMFAO
someone in another board mentioned douche canoe awhile back. i started saying douche canoe at school because of that and now everyone says it.
bitch tits fart knocker (i dont use this one i hate it)
take any curse word (shit, fuck, bitch, ass) and pair it with a body part (tits, dick, ass) and you have instant insults.