Pedro wears a shirt and tie to work every day even though the dress code is extremely lax at his workplace. Most people wear jeans; polo shirts are common but some wear t-shirts.
But Pedro is kind of on the youngish side for the level of work he's doing, and he is sort of baby-faced so people tend to think he's even younger. (He has had people express amazement when they learn that he has kids and a wife of nearly 10 years.) So he dresses up for work (and works hard) so that people will take him more seriously in meetings.
It seems to have paid off -- recently we ran into a woman who works in Pedro's building, and one of the first things she said to me was how she sees him in the break room sometimes, they've never spoken except for a quick "Hello," but she recognized him right away because he was dressed up nicely (for our dinner date) just like he does for work. (In fact, it was Friday night, and he didn't change between work and our date.)