The last episode

I just wished in the last episode it would all be good but the sad ending really ruined my day. I don't know but seriously I loved the characters and their acting but why the ending became all of a sudden a nightmare to c drama watchers. So very much disappointed just because of the last episode. It's not that I'm not telling you to watch the drama but seriously it could have been improved. It is not a good thing having sad ending in such a good drama. Sorry to say this but very much expected from this drama but lost control after the last episode.