Without the pocket square, the top half of your outfit looks fairly sober. Dark jacket. Dark tie. There's nothing wrong with that. However, the pocket square really stands out. The bright orange dominates, and the eye is immediately drawn to it. That's not harmonious. The pattern of your shirt is very similar to the pattern of your square. That's not harmonious. The fold of the square is very business-like, while the color and pattern of the square are very fun. That's not harmonious.