[Retric]

Casual dress code does not include a clown costume, so it's far more constrained than your suggesting.

As to suits it's one of those fractal breakdowns with a lot of varity if you get specific enough. EX: You could say fat vs skinny ties, but the there is a wide range of patterns wich fit a wide range of shirt colors. Not just Red tie on white shirt.

Personally I like semi formal dress codes simply because they have a default and require minimal thought. Where casual has a lot of 'hidden' rules.