Interesting, I tend to agree about the cognitive capacity, but raters than focus (as many others here seem to have a problem with under sleep deprivation), I find that the biggest challenge for me is motivation. Any task that is inherently rewarding (coding fun stuff, games,...) is no problem. Anything remotely boring, or just challenging, I just don't find it in me. If push comes to shove I'll do it, but if I'm allowed to procrastinate I will