I think it is anything goes, because the sphere on influence is so wide. For me personally, casual men's style surrounds Ivy and 50's - 60's Europe, I've become interested in smart men's wear from about 1910 to now especially US, Britain and Italy, as every decade, and country has it's appeal, so I can't begin to say what is best like I can with casual clothes.
For me the principles of form, colour, and style are always at the forefront of clothing. Dressing to excess or to a minimal style still has those rules. When I dress like above it's an over exaggeration, it's me exploring the limits, it's not what I would wear daily. I'm trying to learn from my mistakes, to dress wildly, is fun but will quickly make you look silly, to dress with style and restraint is timeless. To dress conservatively is dull. But you can dip your toe in all three as your mood suggests. And if you can understand what makes each method tick you can begin to break down the barriers between them.
Maybe it'd have been better to get a tie in the colours of the PS, and then use that strong pinky Magenta just in the PS. The grey of the tie is sitting to close to the black of the jacket. And then the greeny/yellow is working as the contrasting colour which is drawing out the PS from everything else. Hmmm, I will ponder on this. Cheers FNB.