Whenever I use microfiber towels to take off wax, detail spray, etc, the towel is so smooth that it becomes unfolded because of the friction on the surface. Any way to hold onto the towel while keeping it neat? Sometimes I just open the whole towel and use it like that.

 

I do the same, depending on the nap of the towel. Seems the thicker the nap the easier it is to use folded. My polishing towels seem to really grab when taking off the polish, and are impossible to keep folded. It doesn't hurt anything.
The thicker Chamois, seems to grab less and will stay folded.

 

I've never had that problem, but I would try to keep the fold in place because it adds extra padding between your hand and the paint, reducing the pressure and allowing the particles to be better pulled away from the paint surface. Hence, less chance of micro-scratches.