It doesn't hurt to have a couple of decent riding jeans. Yes, we do dress for the crash but at the same time, let's be reasonable. Why should you wear riding pants (textile or leather) when you just going to toot down the street a couple of miles for coffee (unless your idea of tooting down the street means redline in fourth gear)?
I can't speak for others but my pants wearing guide goes like this:
1. Just a few miles ride on the streets with no freeway traffic - riding jeans.
2. Everything else - riding pants (textile or leathers depending on the type of ride and weather).