an unnecessary breakup 

Two hands brushing against each other

The male lead appearing out of nowhere every time the female lead gets into any sort of trouble.

do they know something about teleportation that we don't???

Someone faints and gets taken to the hospital

Female lead dramatically tripping over air

A crazy psycho mom or mom in law 

Rich male lead buys everything in the store for female lead

Lead walking in the rain without an umbrella or cover

Lead with strong sense of humor