Treat user effort as a currency. To create a product users love, design the tradeoff curve of use case complexity to user effort with the same care you design your pricing scheme. Alan Kay [source] One of my favorite product design principles is Alan Kay’s “Simple things should be simple, complex things should be possible”. [1] I had been saying it almost verbatim long before I encountered Kay’s quote. Kay’s maxim is deceptively simple, but its implications run deep. It isn’t just a design ideal...