Lesson Context Market Feed
SPY $776.34 -0.20%
QQQ $731.07 -0.14%
AAPL $305.93 +0.22%
MSFT $495.40 -0.30%
NVDA $225.16 -0.06%
XLK $190.01 -0.40%
Module 01 · Concepts

The mistakes that matter most

These are not exotic edge cases. They are the recurring patterns that show up when process discipline slips.

Overfitting
The dataset approved a story the market never did

If the strategy needs too much parameter precision, too many filters, or too much explanation after the fact, the edge is probably not durable enough for capital.

Oversizing
A decent strategy can be ruined by bad sizing

When position size outruns evidence, ordinary drawdowns start forcing emotional decisions, and the system becomes unstable even if the signal logic stays sound.

Neglect
Unsupervised automation is still a risk choice

Not watching health, execution quality, or regime change is still an active decision. The absence of intervention can itself be the mistake.

Stubbornness
Refusing to retire weak logic compounds damage

A strategy that no longer earns desk space should be cut cleanly. Endless rescue attempts usually waste more capital and time than the original loss.

In this lesson
  • The dataset approved a story the market never did
  • A decent strategy can be ruined by bad sizing
Try it — trailing stop

A trailing stop ratchets up as price rises and only ever moves in your favour. Set the trail distance and see where it would have locked in the move on this sample path.

Peak
—
Exit
—
Locked gain
—
The page to remember

Do not let recent outcomes rewrite your risk standards.

←Back to Mistakes & Risk