What is the extend of our confidence to achieve something in life?

I go for a job with my own capability and give it my best. I mostly achieve what I want but if I still fail, there is no regret.

Well, what you have said is true..when I wish to take up a task I see both sides...i mean take both the positive factors and the negative factors into consideration. Being confident is one thing..but being over-confident can invite trouble. Our foot should be grounded and we should always strive for things with a positive bent of mind. But we should also be vigilant and tread cautiously. In short, yes we should be ready to accept that we may not get 100 percent success in any task...there could be chances of failure too.

Sir Winston Churchill said, " Never give up.". Swami Vivekananda said, "Arise awake. Stop not till the goal is achieved." Both the above quotes of seers speak volumes about to what extent one has to stretch himself with self confidence to achieve a thing that he always wanted to achieve.

The 'Extent' of anyone's ambition should not go beyond ground realities they individually face ...Personally I do everything within my capacity to achoeve goals and most of the time a positive attitude helps to a great deal...

One must make self assessment based on physical ability, interests and traits and fix goals which are realizable. Self confidence based on actual appraisal of self is only genuine. Self confidence without real strength is suicidal.

The extent of confidence varies from an individual to individual and there is no fixed rule or a scale to measure it. Confidence essentially comes from one's upbringing, education, economical strata, social status etc. etc. Also what is confidence for one person could very well simply be brashness or obnoxiousness for another person. As long as you are able to weigh out things properly, judge their consequences etc. and feel positive about something, you could be a confident person.

I believe my self confidence and I does not have any over confidence as i think positive before doing a work on my own capability

Thinking positive makes us attempt what we perceive as difficult and if we do well, we gain confidence and a sense of pride.

Not at all by forcasting the probable dangers we can also think of alternate methods to achieve our goals.

Self-confidence is essential for success. We should aim at 100% success; then only we will be able to achieve at least 90% of it. It is good if we can imagine about that negative factors in advance so that there is nothing ‘unexpected’. They will not discourage us, but will give more encouragement to face everything as it comes

Yes we can't achieve whatever we thought. But being positive is import to get that our goals. It is also being positive if we are not regretting our failure and think about getting success for next one. We should just make sure that over confidence is direct way of failure.