"Because I knew there was a chance I might see you today and I wanted to be presentable" is one of the lines I have been using at work when asked "Why are you wearing a suit?" Why?
Because I felt like looking professional today! Why is set such a social taboo to where a suit to work. it is not against dress code, we are not told we have to dress down to business casual, we are told as administrative staff to look the part and dress the part and I think in my case since I am being developed into management staff I am dressing the part of a manager and my desired outcome of being a manager is wearing a suit!