For me it was Propositional Calculus in my undergrad... was being super thick headed about picking it up and failed the mid-term. A friend and I (who was also h

For me it was Propositional Calculus in my undergrad... was being super thick headed about picking it up and failed the mid-term. A friend and I (who was also having problems) sat down with a stack of exercises and just started doing them. I can almost remember hearing the click when I finally got it and it all made sense. Was probably the original click that made me ultimately end up in programming as I found how all the rules worked together to form a way to express ideas beautiful.