The Korean drama formula

Female lead

• exudes carefreeness, slightly forgetful/clumsy/messy
• at the beginning of the series, she will have something important (house, female identity) taken away from her. Recovering this will be a theme of the series.
• plain looks
• likes eating, yet remains slim

Male lead

• relationship with female lead: ranges from indifference to conflict
• will be forced into a living arrangement with the female lead (stay/work together) 
• may be forced into a sham marriage with the female lead for various reasons (parents, media pressure)

Other male characters

• more caring than the male lead
• better status than the male lead - has more money or a better job, but the male lead has a cool factor (is an indifferent musician or actor). Possibly represents fantasy of finding a partner with a risky, exciting job.

Female antagonist

• looks better than female lead, although female viewers will disagree
• holds a higher status than female lead
• shamelessly throws herself on male characters
• has some form of control over the male lead (blackmail, boss), forcing him to reluctantly do her bidding