Heh, when I got a Nexus 4, it was my first glass backed phone. It arrived two days before the case did. I was meeting my wife for dinner and got there a bit early, and had the phone on the restaurant table. When my wife came and sat down the slight wiggle she gave to the table was enough for the phone to slide right off and make the back look like a spider web of cracks. Fortunately it was only the back.
I never go without a case now. The thicker and grippier the better. I also have a belief that phones these days are too thin, and I would gladly have a thicker phone with better battery life. The best feeling phone in my hand IMHO was my Palm Treo, which was almost an inch thick.