Rain or Shine

Here's My Plan has more dark humor while JBL is more soft/melo, but they both have a slice of life feel and show characters dealing with difficult life and family circumstances.

Both leads have suffered loss or trauma and are distanced/cut off from society. The ML has a history of getting into fights. Both have a melancholy tone with a theme of slowly healing.

Similar slice-of-life feels and romance
Romance is slow, steady and understanding (super cute)
Very cute and slightly immature/childish male adults with mature, empathetic and tsundere-like female leads

.............................In both drama characters are introvert and some how it reveals same feeling.................................................

- realistic and flawed characters
- slow-paced romance
- angst and heartache
- love rectangles
- bad parents

Having mentioned this by a couple of users in the comment section, I agree that they are similar in certain ways. Even though The One and Only just have released 2 episodes, I can already similarities in the main couple. They are both scarred by their traumatic childhood that heavily influenced their present lives. In JBL, it seems that the main leads are positively influenced by their childhood (like how they chose their career) but I can not say the same for the couple in The One and Only.

Very different plots, similar characters/main relationship. Both dramas have two lonely, poor, and damaged leads - a FL struggling with issues with her family and an orphan ML who works hard jobs - who become each others' family.

Not your typical love story.A realistic drama about the hardships and struggles in life. A great storyline about finding true love. A must see for everyone who wants tearjerker dramas.A plausible performance from the actors and actresses. I just loved everything about it.It shows the real meaning of love and family.

Mad for each other seems more like a comedy at the beginning but gets more serious as the show progresses. Just Between Lovers is more melodramatic. Both shows have a love story about healing and people struggling with mental health issues. JBL shows PTSD and alcoholism while MFEO shows anger management issues, paranoia, PTSD and social anxiety.

SPOILER ALERT
In both the shows the couple has experienced an accident together in their pasts.
Though the plot in both shows is different they do have a bit similar feel

both Black Dog and Just Between Lovers are similar in their slow and healing nature, both had that cold blue vibes

JBL is more melo and sad, while HCCC is way more of a romcom. But the way the MLs in both shows help and care for people in their communities and FLs in both shows get curious about the MLs and want to know more about them seem very similar. It's also cool that both shows give a glimpse of the FLs' jobs and show us how passionate and skilled they are.

Both leads are isolated due to trauma, with both MLs working hard jobs. Both stories have a melancholy but healing tone.

Leads had painful experiences in their lives, both meet to heal each other's pain. Also, I found the vibes quite similar.

Both dramas cover memorials and loss in a soft, slice of life way. Into the Ring is much more comedic and politics oriented, while Just Between Lovers is more melancholic and focused on the architecture/construction industry. Both dramas explore complicated relationships with parents and the frustration of trying to create change in a world determined to be stagnant. I really love the initiative both FLs take and how confident they are in pursuing their relationships. The main couples' personalities aren't very similar except that they both start out as friends and maintain emotional support for each other even after they start dating; truly two of my favorite drama couples.