why do rarity and fluttershy hate applejack and rainbow dash?

The Cutie Map, Part 1  
Fluttershy: Come on applejack, you’re almost as bad as rainbow dash!  
Rainbow Dash: Don’t drag me into this!  
why does shy throw her rage at dash?
 
Boast Busters  
Rarity: applejack and rainbow dash may behave like ruffians but i have a sense of style!
 
 
Swarm of The Century  
Rarity: Stand still rainbow dash!  
Rainbow Dash: i can’t! i need to fly! this is waay to boring for me!  
Rarity: Do you want to look nice for princess celestia or not?  
was dash ugly? she wasn’t dressing anypony else up!
 
Simple Ways  
Rarity: what could applejack possibly have that i don’t?
 
She steryotypes appplejack as a farm peasant.

When friends are close enough, they can smack talk each other to a certain extent without hard feelings.