just remember this:  when you -50%, you need +100% to make it back to where you came from, and it's almost impossible given that if you cannot make positive investment.

This maths is hard coded to make people lose in investment especially without first understanding risk of ruin.

If you don't know this, you will probably tinkle with martingale and end up ruining your portfolio.

x% traders will lose x% of their portfolio in x days. You tell me what is x=?

1. Be unemotional - use pre-planned If-Then-Else (eg. portfolio rebalancing IF.., IF x falls 20% or more.., IF..), numbers/knowned,
NOT based on feel/crystal balls
Do NOT "plan fire escape during fire". That's where fear & greed jumps on me.

2. All financial plans are useless - it's the planning that is useful.
ie. the logic/reasons/whys. Thus, one can always tweak when things happens or goals moved/changed

3. All financial goals are really life goals.
If i dont have a burning reason WHY i NEED to reach the goals... then.. meh.. i won't carry through

You are right, and my mistake should serve as a lesson to all other young investors alike.
Well I was young and naive back then with nobody to caution me on such stuffs, I had to learn everything the hard way.
But being burnt is one sure way to keep improving yourself.

MBF finance or something?

Your word of "Bogleheads" led me to this thread opening.

Bro, anyone else.. If you wish to read more about failure in investment :
https://www.bogleheads.org/forum/viewtopic.php?t=25126