Last good slice of life / drama seinen I've read is "Undercurrent."
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The manga begins as Kanae Sekiguchi, proprietor of the Tsuki no Yu bathhouse, struggles to reopen her business after the unexplained disappearance of her husband...
Found it be very mature and "quiet" manga, yet never slow or dull. Keeps you in suspense until the final twist. The story unfolds slowly but it always makes sense.
Deals with topics such as facing repressed ghosts of your past, abandonment, and how hard it is to connect to others sometimes, how sometimes we tend to remain aloof and never truly know someone.
I love how the author expresses so many things through his characters faces with little to no dialogue sometimes.
It's a bit tragic but ultimately hopeful, recommended.