One of my friends just sent me an article on self-sabotage - very timely it was too! It seems to be a universal issue like procrastination - indeed procrastination can be an aspect of self-sabotage - but self-sabotage seems to show up in lots of different ways. For me it showed up recently in the form of not doing "homework". I'm on a course that requires a substantial amount of time devoted to meditation and concentration exercises each day. I often don't get it done despite my best efforts but just recently I didn't even attempt to do anything for two weeks - and didn't care about it either. Bit like a defiant teenager!
When I finally decided I had to come to grips with this before I sabotaged my whole attendance at the course, I discovered that a part of me was very angry that I was changing. Of course the whole idea of doing the course was to create change, but the anger stemmed from the fear of what the changes would mean. We're funny creatures - we want change but it's also one of the things we fear most.
This internal conflict between what we want and the actions we take can be seen in any number of situations when we don't do what we know we could do or what would be beneficial for us to do - leaving preparation of a presentation or report till the last moment, cramming for an exam the night before, being rude to someone, turning up late, impulse spending on the credit card, smoking, drinking too much alcohol, eating unhealthy food, knocking back a job opportunity. The list is endless and I'm sure you can add plenty examples of your own.
I like that quote "We have met the enemy and they are us!". It can be very frustrating - but then we beat ourselves up for sabotaging ourselves - which doesn't exactly help! It is the fear of the consequences of reaching our goals that governs our behaviour and what we need to do is become aware of the fear and address that, instead of jumping up and down at our behaviour. Our fear may be about being rejected, making mistakes, being inadequate or not good enough, losing our known identity (big one this), being successful or conversely being a failure, being criticised, being vulnerable, not belonging. It's always fear that gets in the way of us getting to where we want to be.
So in order to move forward and achieve your goals, stop sitting in the frustration and look past your behaviour to what you're afraid of - and then deal with that.