By this I mean that perfectionists tend to be very ego-centric and believe themselves to be amazingly special or unique in some way. They are often afraid of starting or doing something because they fear producing sub-optimal output.
This is because they put too much emphasis on the final finished product or the end result, rather than on the engaging process and complexity and subtleties and sheer enjoyment they could get from the (often overlooked) satisfying process of creation. Instead they seem to think that all happiness and satisfaction can only come from that A+ or that spotless 10-0 record in Starcraft 2.
This is a huge mistake. When you base your happiness and your mental and emotional well-being on things you cannot control (if a teacher misunderstood your argument, or if your opponent gave an uncharacteristically strong performance) rather than on what you can - namely, how hard you work, what you put into the process, how long and how deep you let your creative juices simmer, etc.
I feel like in many situations, people put a conditional on their own happiness...and this conditional often revolves around outside external factors or influences that you cannot control with any degree of certainty. Aberrations will inevitably occur; data points will occasionally fall far from the correlation lines.
Anxiety about producing something that will lead people to have a negative perception of you is a natural tendency. But there is a fine line. You should not feel insecure about your output to the point that you have a mental breakdown whenever anyone raises a possible criticism. Not everyone is going to love you or what you do or what you represent. Sometimes that's going to be because they genuinely feel you did crap, other times it will be constructive criticism, other times they will be bullies trying to make you feel like crap, and even other times they might be jealous of you.
This goes back to not basing your happiness on external circumstances. If someone tells you that your shirt looks like crap, you don't go home and change your shirt. You have the self-confidence to straight up tell them that their opinion means jack shit, you know who you are and how good of a person you are and everything.
But that doesn't mean you should shut yourself off from other people and the world just because you don't agree with everything they say. This goes back to the point I made about perfectionists being ego-centric to the extreme. They are afraid of others' negative perceptions of themselves, but they also convince themselves that anything less than perfect is unacceptable, not only to other people but to themselves personally. They also hold themselves to unrealistically high standards of success without making any reality checks about how, for instance, people around them are performing. In essence the perfectionist gives himself a crutch: my neighbor mowed his lawn in half an hour, I have to mow my lawn in 15 minutes with a blindfold, or else I am a complete and utter failure. That's totally unfair, you are being unfair on yourself.
For this reason the perfectionist believes that it's better to not even try to do something than to try to do something as well as you possibly can and fall short of perfection. This is the perfect recipe for disaster. Perfectionists often have a short temper and low tolerance for creativity of expression or ingenuity. They seem to forget that humans aren't machines. Machines can produce perfect output, but they have been programmed and designed to do so by humans, because humans can't be perfect themselves. Humans seek in machines what they lack in the very nature of humanity. Just as many innovations and inventions and discoveries happened by accident or mere chance or daydreaming as by meticulous calculation and detail-oriented analysis and technical finesse.
This desire to always be perfect is not healthy. It limits your freedom, your potential for growth. It puts a ceiling on how high you can achieve without ever taking into consideration all the non-quantitative aspects of success and fulfillment. Perfectionists do not ever appreciate themselves because they never look at the glass being half full, but always half empty. Instead of reflecting on their accomplishments and abilities, they focus on things they believe they could have done better or improved on. Which is not bad in itself, the thought of not merely settling for the good score or the well-played game, but getting the perfect score of the perfect performance. It becomes troublesome when you neglect the positives of any situation and only look at the negatives, that is not healthy.
Perfectionists do not compete against others, they compete against themselves. That is good, that is how you be the best. Usain Bolt always wants to break the world records...that he set. But you don't push yourself to the point where your body or your mind just can't take it anymore. You have to know your limits and what you are comfortable doing, and always stretch that boundary ever so incrementally further every day.
Basically, you don't be the best, or the star student, or the hottest progamer, by wanting to be perfect. Wanting to be perfect is so abstract. You don't get an A+ on a test by wanting only to get that A+ to the exclusion of everything else, you get the A+ by doing the best you can possibly do and being the best you can possibly be. That means you don't regard every little misstep as a failure, but as an opportunity to improve. Being a perfectionist takes the fun out of life.