I guess in such a list, I forgot a really big one:

8. Sunk cost bias: people just stubbornly hold on to losers (for years!) because they don't want to admit the error; even when sometimes the trade comes back in their favour (which it usually doesn't), they forget the huge opportunity cost incurred.

6. Not accounting for fees, even moderately high frequency let alone day trading is killed by this unless you are very professional and cognizant of it.

7. The grand daddy of them all is basic magical thinking (I want to make tons of money therefore this works) instead of realising the market (indeed, the world) doesn't care what you want. If you don't have an edge the market will just eat you up.

.. which is beyond stupid, not only because so many greedy people actually think they can average 2%+ per day (!? any pro would tell you 1% per day is literally god tier returns and won't last even if you find it), but totally ignore the volatility of returns (which can overwhelm even healthy positive expected value, see Kelly etc.).

4. Thinking drawing lines on a chart gives you any kind of an edge.

5. Not understanding that win rate is irrelevant, what matters is EV and volatility. (3/n)

Also the guy is very honest about his stupidity. He hit one of the top "illogical behaviours of people in the market", namely:

1. Unit bias. Only willing to buy things with a nominal per-unit value that's low (like an educated person I know who refused to buy Bitcoin at 400 Yuan in 2013 because it's "too expensive" ... it's like 80000 now).
2. Taking broad media and public attention as a buying signal instead of selling.
3. Projecting possible trading success basd on "X% per day profit" (2/n)