Many moons ago in High School I was on the Debate team. Like most others, I had joined to beef up the 'ol college application, and hey I like to argue so why not do that as an extra curricular activity?
Of course, there was one thing I hated about the whole concept, and that was dressing up. Those damn collared shirts. Those damn jackets. Those ties tied with arcane means. Back then(and now) you'd be lucky to get me in anything other than a Tee-shirt and jeans, unless you made me. My after-school job was at a bowling alley, so obviously I wasn't dressed to kill there either. I only "dressed up" at debate meets, and I considered that a chore.
Graduating High School I went to Texas A&M,joined the Corps of Cadets, and for the first time in my life "look professional, damn it" was drilled into my head. Polish those shoes! Iron those pants! Shine that brass! Later, after I left TAMU I joined the Navy, and I spent 4 years concerned about keeping the uniform reasonably clean and wrinkle free.
After I got out, I went to Men's Warehouse to get the first suit I had bought in over 5 years. Need to look purty for job interviews, obviously. While I was getting measured and fitted, a father and son entered the store, and the son proceed to piss and moan about how he didn't need a suit and tie, and he would find a job where he wouldn't have to "dress up" to work. I was both amused and irritated, after all even McDonald's makes you wear a uniform.
Outside of work I still dress up to a maximum of a polo shirt and jeans, but wearing a suit and tie no longer bothers me as it once did. Impressions, whether in an IT enviroment or otherwise, are important. Dressing and acting in a professional manner instills confidence in others, and the only way you can get away looking like a hobo in today's world is if you have (1)proven over an extended time period to your employer that you're valuable enough to be given special dispensation and (2)you can be kept out of sight so as to not embaress the company/agency in front of customers/clients.
If you look and act professional, you may even feel proud about it.