Pattern recognition. When I started, all web development was server side preprocessing. This means debugging involved looking at thousands of lines of apache l

Pattern recognition. When I started, all web development was server side preprocessing. This means debugging involved looking at thousands of lines of apache logs. After a while, you got good at picking out the lines you needed to see from the hundreds of lines of stuff you didn't care about. This specific example isn't that relevant to today's web development processes, but being able to notice larger patterns in user behavior, in code use, etc is invaluable.