I agree with
Soredemo, Ikite Yuku - both the main male and female leads are adorably introverted who grow in their meeting each other
Date - similar concept, though this drama is more light-hearted
Love Shuffle - one of the males is a former bully victim who grew up trying to buy relationships, and one of the females is strange, depressed, and suicidal
Also, I'd add
Saikou no Rikon - main male lead is a very high-strung loner type whose personality leads to a failed marriage
These are some of my absolute favorite dramas!