You should not do it if... you can't focus if everything else is falling apart
I have to say, this has probably been one of the most essential skills for me. There is an incredible amount of crazy shit going on in any real start-up, stuff that threatens the very existence of the start-up, on a pretty regular basis. "The world could end tomorrow" seems almost like the standard situation for most of the early life of the start-up. If you can't get stuff done in those conditions, you're pretty much toast right from the start.
I wonder what other skill correlates with this... I've always had an (un)healthy ability to ignore people around me and focus on whatever it is I'm doing (whether it's working, reading, playing computer games, etc). That ability also applies to meta-distractions... I can still throw myself into my work even when I don't know if that work will still have any meaning the next day, or when something really disruptive has just happened in my personal life, or when I'm sitting under a large cloud of uncertainty about my future. Sometimes that might give the impression that I don't care about what's happening around me, but I do - it's just that I can put it aside and focus on the task at hand...
From the same slide:
You should not do it if... you have a low appetite for risk
I would disagree with that, though. Appetite is the wrong word. I don't like risk, I don't enjoy it, and I avoid it whenever possible. However, what I think does help is to have a high tolerance for risk. This is somewhat related to the point above, of course. Tolerance and appetite are different, though.