You have a nice geometric, somewhat masculine look going here. I would play that up. I don't think you need to change the wall or carpet color as they seem to be a nice neutral background. Are they cream? is the purple more plum? and is the blue more of a steel blue/gray? The furniture is chocolate brown? I love the striped pillow on the chair. I would layer a wool steel blue/gray area rug and then play up the blue/plum in the pillows. A wool plaid or blue gray herringbone in a couple of throw pillows (replace a few of the solid color pillows) could help to pull it all together. Kind of like the colors in the picture of this bag. Adding brown leather cording would be a great compliment on the pillows. (Not sure the area rug in front of the TV is adding anything)

Definitely YES!

It is better if you share the pics of the room and sofa. Colors are subjective choice but IMHO, Light blue and lemon yellow looks good with grey and black. Thanks, Nitin Cornerstone Designs, Bangalore.

Keep things cool Cooler shades such as grey and blue help walls recede, making the room feel more spacious and light. Bring home the sunshine Light but warm colours such as terracotta or yellow can mimic sunshine and make a space feel bright and airy. Pale ceilings Keep the ceilings in a light colour to make the room appear larger and lighter. While white is your safest bet, you can opt for mint or sage green for a pop of colour.