Everyone who has done profiling knows that (almost always) the performance problem is in the part that you least expect it. But also that sometimes you wrestle

Everyone who has done profiling knows that (almost always) the performance problem is in the part that you least expect it. But also that sometimes you wrestle to improve the performance of an algorithm hitting a hard wall and than someone comes up with an idea, often resulting from a fresh look on the problem, that results in an improvement of several orders. I guess that performance is at least as counter intuitive as statistics. The same is true for some other things like scalability and reliability. Actually, I think that it scares the hell out of most of the developers that it is so difficult to get a grip on these things. It is so easy to think that there is a simple solution, a grand idea that will fix the problem. I still find myself falling in the trap and this after having developed software for over 30 year. It is the Dunning–Kruger effect over and over again. I guess it more that as a more senior engineer, you have experienced a little more often.