I work an office job, and the dress code is "Business Casual." I like to put a tie on, maybe a sport coat, some nice slacks, dressy shoes, etc. It does a couple of things for me:
1. Wearing a tie makes me feel like I'm actually at a place where I should be presenting myself well, and in a workplace scenario, it makes me feel like I'm working.
2. It's countercultural. I am 25 years old, so business casual has been de rigueur since before I was born. Dressing up that 10% more is, at this point, a countercultural choice. Be a little rebel in your cute little outfit.
3. I look and feel good as hell.
Obviously this won't work for everyone. If you work with your hands, a tie has never been a practical choice. Additionally, if you have to wear a uniform, I'm very sorry for this horrible dehumanization.