Biggest lesson I’ve learned is just how quickly most people turn from super mean to super friendly—if you give them a chance to do so. Nothing worse than waking up to a mean e-mail; yet nothing more rewarding than turning those into long-time customers. Second biggest lesson—do take the time to explain why something isn’t available, isn’t working, isn’t on the roadmap. I am always amazed by how surprised and thankful people are when they don’t get a canned response, but a personal one. It takes a lot of time, but it’s the single-best marketing effort I’ve ever invested in.