So what I've noticed with a lot of Dramas that they often have not so pretty clothes and I just want to watch a Drama where they dont wear dresses with flowers and stuff and just wear casual clothes for example Happiness. 

If i remember correctly "This is my First Life" or "The XX"  are dramas where you find clothes that are similarish to Happiness.

Though i am not 100% sure what you mean exactly. Are you looking for casual/plain sort of wear or are you looking for pretty clothes?