From the looks of it, this is some kind of complicated/busy plaid on the shirt, which to me is a very informal/country kind of pattern, to use FC's terminology. The pinstripe suit is the city/business pattern. Together they're just too odd to me, even setting aside the aesthetic effect of the two together. In my view, the aesthetic qualities of the pairing only exacerbates my initial discomfort.
For the shirt itself, there's an inconsistency between the contrast collar and the fabric/pattern on the body. I think this could be OK if worn very casually with a cotton jacket or something, in that the-original-collar-wore-out-so-I-replaced-it-with-white-but-it-doesn't-change-how-I-wear-the-shirt kind of way, but not with a pinstripe suit.
I realize that there are a lot of patterns. In the spirit of this thread, suppose for the purpose of looking at this that I was required to wear patterned coat, tie, shirt, ps, and pants today.
The stripes of the suit and shirt are not working well together for me in that one, and the pocket square is just out of nowhere. Like not in a contrasting, but complementing, the rest of the outfit kind of way, but in a you got shot with a paintball gun on the way to work kind of way.