Do you wear Dri-fit mainly for athletic pursuits or for everyday use?
Everyday use. It can be very versatile.
If you happen to wear an old-fashioned cotton shirt, does it make you sad? :-)
Yes and no. sometimes old-fashioned is a good thing. But living in such a humid climate, it can be a bit uncomfortable sometimes. Especially outdoors.
Do you find Dri-fit to be more expensive or do you have a reasonably priced source?
When it first started to become more popular, it was a good bit more expensive than clothing made of other material. But now, you can find it just about anywhere, and the price is usually around the same as a other clothing, and sometimes less. 
When I think of Dri-fit I think of shirts.  Are there other items of Dri-fit clothing you wear which are not shirts?
Yes, there are other types of clothing that are Dri-fit. There are dresses, yoga pants, even socks and underwear come in Dri-fit now days.
What fabric did you wear in the world before Dri-fit and do you still have that clothing?
I wore the common, everyday fabrics,  such as cotton. I do still incorporate more "traditional" fabrics into my wardrobe, but I am the most comfortable in Dri-fit.
Have you tried other fabrics similar to Dri-fit like ClimaCool or DryCELL?