It's just my opinion that's all. I don't care for brown jackets (and suits for that matter). Tan can work too, but to my eye light grey creates a nice contrast with dark jackets. I agree that patterned trousers would look like a costume, that was my point. Trousers need to be plain, but a loud jacket creates a incongruous effect since the upper body is busy and exciting but the lower is boring. It's like someone suddenly gained inspiration halfway through dressing up .