Psychologically speaking, you’re going to bring the same patterns of thinking and behaving to your yoga practice that you bring to the wider sphere of your life. If you’re a perfectionist then you’ll probably hold yourself to the same inflexible standards of perfection with your asanas that you do with everything else, and of course the negative self-talk will start up when you invariably fall short of the mark.
There is nothing wrong with wanting to excel or with trying the very best you can, and in fact these are admirable qualities that tend to create successful outcomes. The problem with the perfectionistic attitude is that it’s generally fear based rather than growth based – anything other than perfection is cause for consternation, and being perfect at everything all the time is impossible so there is going to be a lot of consternation.
Yoga is the perfect place to relax your perfectionistic standards as you come to see in a concrete way that your practice does not have to be perfect to be wonderful as long as you take on a mindful, non-judging attitude. Some days you’ll be on and some days you’ll be off, some days you’ll absolutely drill a difficult pose you’re working on and other days you’ll keep falling out of it, but it won’t matter because you’ll feel spiritually and physically energized afterwards, regardless of how it went.
Actually as time goes by and your practice deepens, asanas will cease to be your main point of focus anyway. You’ll treat them more as a gateway to the philosophical and spiritual aspects of yoga than as ends in themselves, so that by the time you reach what you used to think of as perfection in a certain pose you won’t even be too concerned with it anymore. The cognitive behavioral way to manage your perfectionistic attitude towards your asanas right now is by switching your thinking from “If I don’t do this pose perfectly it’s the end of the world” to “It would be nice to do this pose perfectly but if I don’t it’s no big deal, I’ll get it next time.”