Recommend me drama with Enemies to best buddies 

They hates each other from beginning and turn to best friends. 

Each side considers the other to be an enemy, they both hate each other from the beginning and later become so-called best friends:

Lighter versions:

  • Twenty-Five Twenty-One - FL and SFL. They are rivals who compete against each other. The FL initially idolizes the SFL, but the SFL strongly dislikes and bullies the FL.
  • Goblin - ML and SML. It's probably too strong to say they each *hated* each other. But they definitely bickered.
  • Crash Landing on You - The ML's squad and the FL. Again, probably too strong to say hate, but there were threats and lots of bickering.
  • Chief Kim - who can forget this bickering enemies who try to outsmart each other, only to end up being bickering friends with the side of skinship
  • Short - ML and 2ML are Rivals to Comrades
  • King 2 Hearts - not really enemies but more of a spoiled little prince who can't stand (hates) the straight-laced principled soldier. Prince pulls every available prank and commands but he can't crack the pure-hearted soldier that just wants to protect him
  • Sunkyungkwan Scandal - ML and 2ML are from clans that hate each other, and thus they also have this animosity. but they become part of the Joseon F4...