And it wasn't only about knowledge (where one may fairly or objectively argue - at least in perspective - that indeed he didn't know everything) - it was also about opinions.
He would/will/does share his opinion or perspective about something (and trust me, he has his opinions), and then downplay it as being "only my opinion, and what do I know?".
I would, could, should, did and do claim he did and does knows everything!
Well, maybe, just maybe - not everything, but surely, alot.
And yet his stance has taught me to doubt, to never accept things for granted, and to always try and understand the other possibilities, other options, other points-of-view.
Be it other opinions, knowledge in general, and even not take for granted what we are fortunate enough to have.
* Don't take anything for granted. Don't wait until you miss it to realize how great it was. Appreciate it while it's there.