It is like someone smoke a cigarette next to you, while you are eating something delicious.
I actually hate spoiles! In general, I love asian dramas because there is always a unpredictable point: A twist, a character or something else outstanding. If someone tells me this facts before I already watched it, it ruins the whole drama experience for me.
An example:"The end was shocking and made me cry" my thoughts: thank you! at least YOU was surprised and emotionally involved... because I know there will be no hope, I will not feel it.
There will always be people who cannot understand that other people are different. If they don't care for spoilers, they don't understand why others do.They don't even get this thought. They just want to share their feelings even if they annoy others with it. So they are not evil or mean... just kind of ignorant and not empathic... even so... it is unfair :(