Why do we feel ourselves failure due to depression?

Because when we're depressed we can't visualize the positive points about ourselves, even if others repeatedly state them to us. It's a common characteristic of depression.

We feel ourselves fail because when we are on a depress state of emotion our self-esteem are very low. People who feel this way should receive or seek for help, and if you encounter a person experiencing this type of situation, you can try to converse and figure out a solution.

Depression affects the way you look at life.. The way you see yourself.. It brings you down to the point you feel like you're sinking into this deep hole and you're trying to climb out of it but you just cant..and sometimes it's like a fight that you lose the strength to fight....

Depression tends to cloud someone's perception, and generally leads to high levels of negativity. You may have got a little less than you were hoping for in an exam, so your brain kicks in with 'I could've done better' and then that negativity grows and grows.

During that condition (depression), the person is not able to see situations clearly. Everything is based of presumption, colored with negative thoughts. This is not rational thinking

depression affect our perspective in life and how we see oursleves, it prevent us from seeing the positives and pushes us to be harsh on our selves, check this article on 8 Suggestions for Strengthening Self-Esteem When You Have Depression http://psychcentral.com/blog/archives/2013/01/24/8-suggestions-for-strengthening-self-esteem-when-you-have-depression/

Depression gnaws on your confidence and self-importance. You'd feel that you're nothing but a wandering speck of dust seeking the light in life. And if you let the parasite of depression feed on you, then you're already a victim and allowing yourself to be vulnerable to self failure.

When your depressed you tend to think, "I Don't". You tend to compare with others and usually end up seeing yourself in a bad perspective. You tend to copy the lives of others at some point, trying to better yourself. But that's hardly possible, coz it's not so possible. That is one common reason why you tend to think that you aren't worth it, or perhaps that you are a failure. You gotta try to be yourself, bring up your OWN personality on your face, instead of trying to solve your problem with the solutions of other people's problems.

I believe it's because depression makes you not want to do anything. For me it's more like an eternal numbness followed by sudden moments with uncontrolable waves of feelings. Since it makes you feel unstable, it doesn't let you do anything. You can break down over the most dumb thing and getting out of bed can feel as hard as struggling with a thesis. Suddenly you start to dislike everything that made you keep going: music doesn't seem to sound the same, writing doesn't fill you anymore and all of those projects that kept you alive seem more imposible and unrealistic than ever. Of course you're going to fill as a failure if you can't get anything done...and don't enjoy anything at all.

Depression acts like an evil monster that is ready to come out and play. When it does, it tries to drain us from everything that we love and want to pursue. In order to overcome this, you have to tell the monster that you want to feel more positive energy than the negative ones. No matter what happens, you are progressing to your ultimate goal.