Do you believe it can happen ?
According to NLP (Neuro Linguistic Programming), your behaviours in an activity are affected by the beliefs and values you have associated to it. As an example, say you want to become better at public speaking (behaviour) and you take some classes, but despite all the training, deep down you don't believe you are any good at public speaking, then when it comes around to standing up to speak, your body will respond to your beliefs and your voice will waver, etc. Then, when you get some feedback, you'll filter it through those beliefs, e.g. if there are two people both of whom are equally talented but one has the belief that they are a great public speaker and the other that they are not, then if they both get told that they are really good, one will believe it and use that comment to reinforce their belief further, whereas the other won't believe it and will probably find a way to use it to back up their belief that they are not.
This is all well and good but what has this got to do with Stock market trading? Well, part of your success or failure is related to the beliefs you have. If you don't believe that you'll ever make a profit or successfully trade at a new level of outlay then you will find a way to make that happen. This is where self sabotage appears. Where you do something stupid, knowing it's stupid, but do it all the same. NLP offers lots of processes for changing beliefs but sometimes, just realising that a false belief is present, can help bring it to the surface so you can start breaking it down and challenging it.