Even though CPUs have got a lot more complicated, it is t that difficult to make intelligent decisions about optomizations at a high level of abstractions. There are situations where it makes sense to delve deeper as well. Not only because you are writing assembly, but also if you want to handhold the compiler. There are absolutely situations where it is not worthwhile to worry about optimizations. The problem is that the internet peanut gallery is rarely in a postition to give good advice about this.