A lot of Japanede dramas where romance isn't the main genre but somehow, romance was subtle so your hopes kinda goes up, or they love to throw romance angle in between characters and so but won't give them a real ending like the romance part was nothing but a filler.
Example is Jimi ni Sugoi, they didn't end up together, even though FL likes ML a lot, but she chose to pursue her dreams. Still, they end up as friends.
-Dame na Watashi ni Koishite kudasai - not clear If they were together or they reached an agreement to try or work their relationship.
- strawberry night (2010-2012) -this is a detective drama but one can see the chemistry between FL and ML and ML having very obvious feelings for FL but in the drama's SP , the fl ends-up with a yakuza and they had a sizzling affair.
- It's not that I can't marry, but I don't want to- twisted ending, so obvious the leads have fallen for one another but they didn't give us that ending.
- Survival Wedding - maybe it's just who wanted the FL to end up with his boss, but I guess that was never part of the story in the first place.
- Okitegami Kyoko - FL has 1 day amnesia but there was an episode when the leads clearly stated their feelings but for some reason, still open ended towards the end.