The single most important factor in a lifetime of successful investing is your own behaviour.
You could have the greatest portfolio ever created. But one poor behavioral mistake a decade, and you might as well have just kept your money in the bank.
In fact, I would argue that portfolio design, asset allocation, and products only matter to the degree that it influences your behaviour.
So, the next time some person on the financial pornography network or from the financial expert complex starts talking about how you should buy, sell, or do anything at all, just remind yourself: none of that matters if you don’t behave.