Shoes are typically of thinner material in the toes than around the ankle, but human toes are more cold-sensitive than ankles, because toes have a greater ratio of surface area to volume (thus greater heat loss) and are further from the core of the body, so get less warm blood supply. Similarly, pants are usually thicker on the butt (due to pockets) or the upper end in general (suit pants lined to the knee), in spite of the legs requiring more warming than the pelvic region. Suit jackets are open on the chest, but overlap on the belly, which needs less extra insulation. The same suboptimal distribution of warmth characterises various V-necked upper body clothes. Jackets are also thicker on the front than the back, despite most people’s backs being more cold-sensitive than bellies.

This impractical design can be explained for men’s jackets by the desire to improve the wearer’s looks with the visual illusion of broad shoulders created by the V-shape of the front of the jacket. I have written about this in more detail: https://sanderheinsalu.com/ajaveeb/?p=885

For other clothes and shoes, there seems to be no reason for the suboptimal distribution of thickness, which would be easy to fix in the manufacturing process. The extra layers of cloth added by pockets could be balanced by using thinner cloth to make the pocket area of the pants. The pocket pouches on jeans for example are usually of thin cloth, which is a step in the right direction. However, the surface of the pants covering the pockets is usually of the same cloth as the legs. Lining could easily be added to trouser legs to make these as thick as the upper part, compensating for the extra layer of cloth by manufacturing the trousers out of thinner material overall. Similarly, adding a layer to the back of a jacket is easy.

The only difficult part to compensate in the impractical thickness distribution of clothing is the thin chest cover (relative to belly and back) of a V-neck jacket, but this difficulty only arises from the desire to preserve the look of a V-neck. A similar visual illusion of broad shoulders could be created by painting a V-shaped pattern on the garment.

A different impractical aspect of shoe design that can be explained by fashion is the pointy toes. The tapering tips create an optical illusion that makes the feet seem longer, which does not necessarily improve the wearer’s looks. However, fashion is frequently ugly, as evidenced by the web search results to the phrase: „it’s called fashion, look it up”.