Colour harmony is an important thing to consider while choosing colours. There is no such thing as an ugly colour, only colours that are used incorrectly
Before choosing the colours for your space think about the ambience you want to create. For example if you want to design a living room, it should be bright, energetic and inviting. But in the case of a bedroom, it should be calming, smooth and relaxing. That simply means you need to figure out what colours work where.
Green colour is calm and give a feeling of freshness, red is stimulating just like black, orange is energetic and welcoming colour like yellow but blue is calming, relaxing and serene.