Three things the average return will not tell you.
01
The number on the brochure is the average. The number in your account is the CAGR. They are only the same when the path is a straight line, and no real fund rides a straight line.
02
Volatility is a tax, not a feeling. Read it as the swings squared, divided by two. Bigger swings, bigger bite, every single year, taken before you ever see the headline number.
03
A smoother 11 beats a wilder 13 once the horizon is long enough. This is why drawdown matters and why rebalancing earns its keep. Cutting the swings is the same as raising the return you actually keep.
The average return is the story the fund tells. The geometric return is the receipt your money writes. Read the receipt. The gap between the two is the volatility tax, and nobody mails you the bill.