Hesitation – fear of putting on a trade where price signals an entry because of what you think could possibly happen. Hey, it’s game of probability, and you’ll miss 100% of the shots you don’t take.
Chasing – running after the trade you hesitated on because of thinking about it too much, and now you think it will go forever without you. (It may go a long way without you, but don’t worry, another train will come along in a while.)
Overleveraging, averaging down, letting a loser run, trading without protective stops – all caused by the fact you are so certain price will do a certain thing that risk management is for stupid amateurs who get shaken out of “good” positions just when price is about to finally run their way.
Trading against a strong trend – you think price has run too high or too low because you have special indicators that tell you price is “overbought” or “oversold” and therefore has to reverse, even though price is showing you otherwise.
Taking profits too soon – you think no one ever went broke taking a profit and you think that normal price action retracements are reversals, so you grab tiny profits, while allowing losing trades to hit full stop, leaving you with a very poor reward:risk ratio.