Because there are many definitions of what ego is, this article will only look at it from the standpoint of how it is holding you back when interacting with other people (especially women).*
The one thing about ego is that to some degree, everyone has an ego that influences their lives. How we choose to deal with it, is what makes the difference.
How Does Ego Affect You?
Let's first start by explaining how ego hinders your success with women. Also, even when you don't have a big ego, you would still be surprised how much it affects your daily behavior. With that being said, let us take a look at some examples where a big ego can negatively influence interactions with women:
Ego puts you on the defensive. If you're ever been in a situation where another person has said or done something to upset you and you couldn't just let it go, you reacted from your ego. This is exactly how your ego keeps affecting you – it makes you take things personally and puts you on the defensive because you think your worldview is threatened. Aside from all the obvious reasons why this is bad, it's also really messing with your chances to attract the opposite sex.
One thing women are really good at is to get a man to react to them. To see if a man is who he pretends to be, women will test him by saying or doing something (sometimes even ignore him) to provoke a response from him. If he reacts by becoming defensive, confrontational or just butthurt (lets his ego dictate his behavior) he's out. However, if he stays congruent and unreactive, he will be perceived as more attractive.
Your ego can also influence the way you react to other men by becoming confrontational when insulted. This is not something to be proud of, nor is it attractive to women when you try to defend your "honor" by starting a fight. Instead of letting it go, you will make things worse because you acted out of ego.
The solution to this problem is simple – not giving a shit what others think of you. Although in practice it does look hard, try to remember that in the grand scheme of things it doesn't matter what someone says about you. When your first reaction to a provocation is to go on the defensive, you are fighting a lost battle. However, if you don't let yourself get influenced by what others say or think about you, no one can faze you – you'll be untouchable.
Ego creates fear. Your ego can hold you back in many social situations. When your fear of negative reactions from others is too strong, you won't express yourself as freely as you would like to. You will restrict yourself because of fear that the things you say or do might not be good enough. If you ever hesitated to go up and talk to a woman, it has mostly been because of this problem. This fear response is your ego's way of protecting you from the possible outcome: rejection.
If you can avoid letting your ego get in your way and face these fears, your social interactions will improve. Besides, nothing bad will actually happen to you should you get rejected. You just have to learn not to take it personally because it rarely is. Also, if you let go of your ego, you will have the balls to approach every girl you find attractive because you are not afraid of making a fool out of yourself.
Ego keeps you from succeeding. Ego is this strict, rigid belief system that holds you back from becoming a better you. For some guys, ego is the reason why they refuse to learn pickup in the first place, although they have no idea how to attract women. They simply can not accept the fact that the only reason why their circumstances suck and why they don't have any success with women is because it's their own fault. They would rather remain in ignorance than to "stoop as low" as to learn how to become better with women or to improve their lives by trying and risking failure and humiliation.
This is also a part of the reason why many men won't push themselves out of their comfort zone – they are afraid to fail or make a fool out of themselves (the other one being: it's just too damn hard, man!). Because it's always easier to find excuses why you don't succeed than to face the truth.
If you let go of your ego and admit to yourself that you are the one responsible for your shitty situation, you will start to grow in ways you never did before.
Ego makes you compare yourself to others. Whenever you let your ego guide you, you start comparing yourself to other people because you doubt your own worth. This leads some guys comparing themselves to other men and seeing themselves either as superior or inferior to them. Neither of these mindsets is healthy because they influence how you react to others and how their presence is affecting you.
A lot of guys compare themselves even to the opposite sex. That's why most have rarely problems approaching average girls but are terrified of hot ones. It's because they compare their own worth to the girl's: if they're "better" than the girl, they have no problem approaching or even embarrass themselves in front of her (or getting rejected), but when she is "too good for them" the approach would be terrifying and a rejection would mean they are worthless.
This is why it's important to let go of this comparing to others. If you want to become the guy girls admire, you have to be humble and not try to one-up others or see them as a threat. You have to see yourself as an independent individual whose surroundings do not affect him and who doesn't feel the need to validate himself by always drawing comparisons to others.
Getting Rid of Your Ego
The first thing to understand about your ego is that it is very hard to get rid of. And unless you want to become a Buddhist monk, you aim shouldn't actually be to get rid of your ego completely. What you should do instead is trying to acknowledge it and realize that it is holding you back from doing the things you want to do. Instead of fighting it, you should just accept that it's a part of you and act despite it.
Always remember to let go of things that don't really matter. Things like what others (especially strangers) think of you or how situations might affect your "status" aren't that important. In the long run, they will be forgotten and no one will care to remember. And, you're not doing yourself any favors if you're constantly comparing yourself to others!
But no matter what you do, most likely, you will have an ego until the day you die. It will always be there, trying to "protect you" from outside influences and keep you safe from dangers (like approaching and getting rejected). It will try to keep you the way you are. If you give in to it, it will restrict your growth in many areas of life. However, if you choose to act despite what your ego tells you, you might even learn something new. It's your choice.