meaning of Halloween

NOTE: This is not a scholarly article on the history of Halloween.
I wore a full formal business suit (but without a vest) to work today. Normally, the dress code is business casual. And then I decided to top it off with a Santa hat.
Actually, it doesn't necessarily have to be a "Santa" hat. It is simply a thing that looks like a Santa hat and can be worn as such. The point is to wear something different. If I simply wore the suit, nobody would notice that I'm actually wearing something different. But I think it did actually startle the department manager because she thought I was going for a job interview! Not a wise thing to do, I guess. When they intend the dress code to be business casual, they intend it to be business casual. Wearing something less shows lack of cooperation. Wearing something more may make people think you're trying to prove something. Either way would be disrespectful. Hopefully my "Santa" hat diverted attention. Anyhow, I don't think I'll ever wear a suit again in that office unless actually expected of me. People can't read minds and it's probably better just to wear that hat so that I don't have to explain myself and hope to save my ass that way.