To repeat, we do this for FUN. So why do it if it isn't fun?
You're answering a slightly different question -- and don't get me wrong, it's an answer worth giving. A much underrated and perfectly valid reason for cancelling a flight is "I just don't feel like facing that particular challenge today". When people make fatal mistakes in aircraft, it's often because they hadn't fully committed the time and mental effort required to get it right on the day.
The issue for Penguina seemed to be more about
not knowing what the weather would be like. If you only fly in perfect conditions, you'll never learn where the line is between fun and misery.
I was rather struck by one of HWD's comments:
But not when the base is 2000' or lower ('cept in circuit) or any adverse effects present within 100 miles!
What's an "adverse effect"? Do you mean you don't fly if there's a thunderstorm within 100 miles? Why not? If you can
see convection, you don't have to fly
into it. But if you abort a flight every time there's a PROB30 TEMPO SHRA on the forecast, you'll never find that out. The x-wind would worry me much more, because at some point you know you're going to have to deal with it.