Everybody is shit here and I don't feel for any of them.
Your emotions will be wasted if you feel for them anyway.
Satomi is obsessed with that one promiscuous guy who HAS feelings for her but still wants to keep being friends with Kanji, knowing that both of their lives will be a mess. For what, you ask? Let me quote you Satomi's friend in this regard.
Mikami is in love with Satomi but still cheats on her again and again. Talk about typical rich guy syndrome spoiled with too many flavours.
Kanji, you need to take control of your life. You make lemonades when life gives you lemons. But you don't have to make a bomb and blow yourself up if it gives you explosives. He doesn't know when to run away. I hate how Satomi appreciates his overly frank persona but also ultimately takes advantage of it. Kanji, if you can't win the girl, just do yourself a favour and leave. Don't go throwing your life into a mess just because of that one girl. He isn't a high school kid to not understand this, and neither so naive having been went through romantic relationships in the past.
Rika is just, Rika. She is a selfish person and she knows this herself. If you didn't know, she will cheat on Kanji and get pregnant with the Boss's baby. To all the people who were angry with the drama's ending as to why Kanji chose Satomi over Rika, this is why. I don't know if this was a deliberate deletion in the drama to add to the complexity.
Yes, we humans are all shit. But this fact is rubbed in when there is a conflict between the kind and the selfish side of one's personality as seen in case of Kanji. Pertaining to the story, this conflict is aggravated further when it comes down to life-changing decisions in situations meant to emulate real life..