How to change myself? It seems that no matter how much I meditate, practice mindfulness, read dhamma books and attempt to follow the 8fold path etc it only takes one little thing to happen and I just instantly revert to very entrenched maladaptive, negative, and I suppose conditioned thoughts and behaviours.Then I feel lots of shame, hopelessness and guilt etc. how do I work with this and change myself for the better  permanently?   I've changed a little since I begun about 6 years ago but I'm impatient as life is going by very quickly, I'm getting older and I want to be happy and live a fulfilling life  but I keep thinking, saying and doing  things that are not conducive towards that. I don't have much hope that I'll ever make any lasting positive change.  My brain seems to be wired to fail.   How can buddhism help me with this conundrum?
So a client hires me as their personal trainer.  They say, "I've been working out for five years.  I never see any results.  I just don't think I'll ever get into shape!"  I ask them to workout for me.  They go from machine to machine doing all sorts of bizarre rep schemes.  They take five minutes between sets.  They use weight that's easily 50% less than what they should be doing.  They get on the treadmill and do ten minutes at about 2.5 MPH.  I ask them how often they do their workout out.  "At least once a week.  Sometimes twice.  Sometimes I don't go at all."

I put them on a basic, consistent, progressive program.  Since they are paying me $25 an hour whether they come or not, suddenly they start going to the gym with more frequency.  After six weeks, they've seen more progress than in their previous five years of training.

Seng Ts'an says that "to live in the great way is neither easy nor difficult, but those with limited views are fearful and irresolute."  If I was to look at your practice, how much would it resemble one of my fitness clients?  Are you really showing up or are you just going through the motions with your practice?

Simple exercise regiments often work just as well as the most complicated.  The deciding factors are effort and consistency.  The Buddhist path is no different.  At most, there are three things to keep in mind - sila, samadhi, and prajna.  Practice these three things wholeheartedly and you will make progress.  It's absolutely inevitable.  This means paying close attention to the precepts, meditating every day for at least an hour, going on regular retreats, and meeting often with your teacher.  It also helps to sit with a sangha.  This gives you accountability in a way that practicing by yourself simply cannot.  

You can change, you simply have to work at it with everything you've got.  If you get derailed, simply get back on the cushion and keep going.