1. I could not be certain on how strong is the moat, and never be sure how long the growth would continue
2. I put too much focus on the current-valuation, those companies had never been cheap.

If #1 is true, then you probably did the right thing by avoiding them, despite leaving money on the table.

If one had to have only one skill in investing, it's the ability to see around corners to see where a firm's moatiness is headed. If 5-10 years later it's still true that nobody is successfully competing with and undercutting their oddly high return on assets and equity, it will work out well. So just concentrate on finding those.

And, perhaps more importantly, staying away from the ones where you don't have that certainty, even realizing that many of them will do very well. If you can't see the moat and ramparts clearly, and the investment works out well, you were just lucky. Missing out on those is not an error, it's prudence.

The ones I kick myself for are the ones where I WAS that certain, and I didn't invest, and they (predictably) made a fortune for their shareholders. Or, perhaps more annoying, the ones where I closed the position for a quick profit.

Jim