I don't agree - mostly. Losing is what happens when you get experience, it means having a go when you aren't ready to do it, but then you're never ready, you just have to try and few times to get it right. And before you can have a big success you may need to have a big failure - it just shows you are the sort of person who tries for big things.

If you keep waiting until you know how to do something perfectly you will never do it. On the other hand, there is such a thing as common sense, what we're talking about here is getting as ready as you need to be - not as ready as you possibly can be, there is a big difference. Be prepared so you don't fall at the first fence, or what's the point? Be prepared so you actually have an experience, but don't keep putting off having a go because you could do more preparation.