To choose or not to choose

How much faith a person should have in his own thoughts? I know the theoratical answers: 100%. Now give me some practical answers.
If i think that i can perform much better and hence get better returns both in terms of money and satisfaction in some other field, should i leave my job and start pursuing my carrier in that "other field"? When i was living with my friends in Chenaai, so many times we had discussed that a person can earn more by opening any normal North Indian Dhaaba than working in most of the indian comapny. But as usual we all are still working in same or different companies. We never opened any Dhaaba.
What was the problem? We all, were 100% confident of this business, But we had never done anything related to that. So, we were not aware of the challenges the business could have thrown on us.Also, whatever bad you speak about your company, one thing is sure, that if you are there in their payroll on 30th/31st of the month, ur bank account will become fatter on that day. Even if, what u have done for the whole month is chatting, forwarding mails and discussing about the bad performance of Indain team in WC.Now why would you want to leave this "pay without work" job and do something in which you will get what u have done (And you don't have the excuse of partial managment also).
But then, how will you feel when u will be 50 or 60 year old? Won't you feel that your life would have been better if you had opted for what you had thought was correct? This can go other way also. If u opted for "ur thoughts" and became a failure .....leave the age of 50 or 60 , u will start cursing urself at 35 only...and this time ur whole family and friends will be with you. All of them will say "bada hero banne chala tha.... pata nahi kya khujaal tha ...achha khaasa kama raha tha"....
so what will be ur choice?
when i was in college, once some of my friend was weighing if he should stand for an election. Because it was 100% sure that he could not win. I had told that "not participating does not mean that you have not lost, rather it gives ur opponent more easiness and comfortable life." So why not fight and loose? We will be more happier or atleast our oppenent will be more upset. So we fought and lost. But that was college and the stake were low.
I have to choose for myself.