Most of the time, I buy men's shoes for the simple reason that I tend to like the styles much, much more. This does not usually create a problem. I have fairly small feet, but a men's 6.5 or 7 is usually fine for me.
The average female foot, however, is narrower than the average male foot. For this reason, women's shoes are usually constructed narrower than men's; "medium" width for a women's shoe is "B," but for a men's shoe, it is "D." The difference between the two widths, for a given shoe, can be anywhere between a half and a full centimeter (as this chart demonstrates).
Usually, the extra room is no problem. If I'm clomping around in boots or skate shoes, it's no big deal. The place it matters is athletic shoes--for me, particularly running shoes.* If you don't want to twist an ankle or mess up your stride, you need running shoes that fit snugly in length and width. Since I've got narrow feet, this usually means women's shoes.
No. No. No.
Often, I end up with a choice of something in pink or pastel blue. Not that I mind those colors, say, on a tie, but I feel silly in pink running shoes.
Sometimes there's a plain white option, but they're so nondescript. I don't want plain shoes, just shoes that don't look like they were designed to match a purse.
I want cool colors! Navy blue, forest green, orange. I can't go out in my navy blue REI vest, grey shorts, and black running shirt, then add pink shoes into the mix. It just makes me feel absurd.
As a result, when I look for running shoes, I don't just seek a good fit. I also look for a decent color. More than once, I've tried a shoe on, had it feel great, but declined to buy it because I hate the colors. I always feel a little childish explaining to the salesperson, "No, these are great, but... I hate the color. No, no--powder blue won't do, either."
Sure, a few things help. You can go to a good running store or buy online where there's more of a selection. And some brands are better than others. But I still look with envy over at the men's section, where there are so many cool colors and styles, compared to just a few I like in the women's section.
*Thanks to my DGF, for giving me the idea for this post!