Koi to Uso was a bit of a strange anime as it explored an interesting solution to a depopulating Japan, which is to force people to get married when they hit marriage age. The annoying thing is that it never really followed through on that plot and kinda diverted to a weird love triangle storyline that I actually can’t remember the ending. However, the OP theme was an instant hit for me with its great catchy tune and weirdly memorable music video. I’m not sure I’d recommend the anime, but the OP is definitely one to look at, here is Kanashii Ureshii by Frederic.