I'm genuinely surprised that you make only two typing bugs per year. I make about 2 per minute, and I consider myself a good programmer. My higher frequency may be in part because my style of coding relies heavily on the typing system: I recompile after about every line of code I type, and make sure my code always type-checks, so maybe I'm not as carefully planning my programming as somebody who's accustomed to dynamically typed languages. Nevertheless, I find it hard to believe that you don't trip up when you create deeply nested loops/recursion. If you don't, what's the trick?