That's not what I'm saying. If a web page takes 2s to render rather than a theoretical minimum of "immediately", for most software that most people write, no one will die, or be hurt, or even feel too bad as a first-order effect. Obviously, if one is writing flight control software, or somesuch, then the stakes are higher, and one ought to be aware of that. That's the practicality calculation. If you're going to kill/hurt/really upset someone, then what you're doing is not fit for purpose (unless that is the purpose :) )