I hate tucking shirts in (button-down, or any other kind) so always wear mine untucked unless a work setting demands it. I don't even tuck them in for social events because I don't go to the kinds of social events where tucking a shirt in would be required.
I have a general distaste of "dressing up for others" that I think stems from the first job I had after college, working for an EXTREMELY conservative IT company in the early 90s. We were required to wear suits and ties, and had to keep our jackets on at all times (except when sitting in our own cube), even on the customer's factory floor. I even remember running cable under a raised data center floor with my jacket and tie on. Some of the dumbest people I worked with there were cherry picked for assignments just because they dressed up and played the part. I contrast that with my time spent in Silicon Valley, where some of the smartest, most successful, and fun people I worked with wore jeans, t-shirts, and sneakers to the office.
It was a bit of a culture shock for me moving from California back to Colorado because I took a job at a company run largely by old school lawyers. Even though I was in IT, they worked on a different floor, and we never had customers on our floor, we were still required to wear business casual every day. Not a huge deal, but I still don't see the point of dressing up to impress the person in the next cube. If you work somewhere where customers are coming in the office, then yeah maybe I can understand it. But if it's just internal people, I don't see the point of having a dress code, as long as people aren't going overboard and wearing stuff like tank tops and flip flops.
