Okay, gents, I'll make this quick. Here are six things that men should not be doing while wearing a suit. I see these violations WAY too often as I walk the streets of this city. I'm going to identify these things, as well as some alternatives in an attempt to save these men from themselves.
1. White athletic socks with dress shoes
This is a no-brainer. It may have been acceptable when you were five years old going to a Sunday morning church service, but even that was pushing it. Figure out if you're a solid or a stripe/pattern type guy, buy a couple decent pairs of dress socks, and call it a day.
2. White T-shirts or A-shirts (“wife beaters”) under light-colored dress shirts
Let's assume you're a sweaty dude who wears undershirts because you worry about sweating through your button-up. Your best bet is a heather gray v-neck shirt. A close runner-up would be a heather gray a-shirt. Why? Both options are closer to your natural skin tone, and won't show as clearly through a white or light-colored dress shirt… Basically, gray blends better with your skin, whereas white stands out, even underneath.
V-necks are better than the standard crewneck in case you plan on loosening your tie and unbuttoning that top button. You don't want the ribbed collar of your crewneck poking through; that just screams “sloppy”.
Make sure to buy undershirts that are fitted and form to your body so you don't have excess fabric bunching and billowing when you tuck in your dress shirt.
Do I even have to explain why this is a no no? Unless you're in a rodeo runway show on a cattle ranch in Montana (…what?), stick with a simple, unadorned belt with a basic buckle for suiting and trousers. Keep it classic and you won't run the risk of looking hokey, costumey, or dated.
4. Sporty sunglasses
Stop it! Oakley and Arnette sunglasses are designed for participation in an active sport, not for going to work. Sticking with aviators or a pair of Wayfarers are your best choices. You may have to try on a couple pairs to find the best fit for your face, and if you're absolutely lost, ask for assistance from a (knowledgeable) salesperson to find out which frame fits your face.
Alternatively, read up and figure it out yourself.
Gents, I understand you have things to carry during your daily commute. Do yourself a favor and rethink what you use to tote your stuff. Nothing looks sillier than a man in a suit schlepping around a Jansport with 12 pockets. You're not a schoolboy, nor are you on a weekend hike.
If you must sling something over your shoulders, at least get a decent messenger bag. It's more professional, with the same amount of functionality as your old backpack. Many models have multiple compartments to store your laptop, notebooks, pens, and everything else you'll need… but unlike a backpack, a leather messenger does so in a grown-up way.
6. Riding a Razor
It is NOT okay to be “commuting” on your Razor scooters. I don't care if the bus stop is twelve blocks away from your office. You are an adult, and you look like you just conned a 5-year-old at the local playground. WALK.
Gents, please do everything you can to avoid the aforementioned violations, and instead, explore the more adult alternatives I've suggested. Attention to detail matters, and staying away from these no-no's is a step in the right direction.