There are some things that most guys (including me) will never get. Let me demonstrate.
Case 1:We cannot distinguish colors between purple,mulberry, orchid, lilac, lavender and so on. Purple is just one color for us and beyond that it can either be light or dark. Same goes for colors like beige, mauve, etc etc.
Case 2: I fail to understand how accessories are so important to an outfit. For any guy it will be one watch and maybe a set of shades. But most females will pay just as much attention to the extras like handbag, earrings, necklace, shoes, etc etc. as the pay for the outfit.
Case 3: Women will always have problems buying shoes. If there is an online store eg. finishline.com then the female will first search by color/design etc. before coming to the size aspect. The guy will first filter it out by size and then depending on brand/design/color and so on. Thus this will invariably lead to females buying up shoes which definitely will look great and may not be the most comfortable to wear (since they filtered out the size aspect at the end)
Case 4: If a guy gets a giftcard as his birthday gift he will be happy that someone did think about him enough to get him something. But if that same giftcard is given to a female then rest assured you will never hear from her again for the rest of your life.
Case 5: Hairstyle for a guy is either long,short and same goes for hair color, black or not and quantity too, you either have hair or you don't. But now for a female this becomes the litmus test whether you think about her enough or not. If you do not notice even a slight tweak in the hair settings then you will never hear from her again.
Enough for now but expect more cases in the future.