Why do I always think everything I do is wrong?

It's a question that can only be answered at the personal level. Such insecurities regarding one's abilities can be caused by many reasons. Pinpoint the reason to uproot the cause of your insecurity.

because you are your own worst enemy. You know all your flaws and your weaknesses. You can also easily neglect yourself. You just have to remember this fact and learn to have a bit more faith in yourself and in your abilities.

with most things in my life i find myself always trying to better myself and not focus on getting the actual job done, sometimes if you just take one step at a time and not always try to perfect things you will find that in the end you wont thing your doing anything wrong

because I can accept myself and make peace with my past, I know myself well enough, and I am grateful for that.

It sounds like you have some self confidence issues, when we think that we aren't good enough, it is easy to think that we can't do anything right, try to take time to appreciate yourself and learn to love you.

May be that is what you understood as a child from your caregivers/surroundings and it manifested in your inner self, so you might not value and trust yourself

There are a variety of possible answers to this question; and it is difficult to answer this about you and your situation without context. Off the top of my head though, your cognitive and emotional processes may be distorted, and it sounds like there could also be some anxiety or guilt in the equation. But please do not mistake this answer for an absolute truth or a medical diagnosis. Talking to a therapist about this might help you.

It can be that you are not confident with your own abilities. Love yourself, don’t doubts your abilities and do things with confidence. Everyone does mistakes.

This may be down to a lack of self confidence. Perhaps you should try to take a few deep breaths and with a bit of paper and pen, write down both the pros and cons of what you do.

Maybe you're lacking self-confidence, or you've experienced many failures in your life that made you believe that you do everything is wrong. Just remember that failure doesn't mean you're wrong, it means that you're gaining experiences.