If you're trying to solve a simple, predefined problem like doing a depth-first search, thinking everything out beforehand doesn't hurt. But few real problems are like that. In real-world applications, you don't usually know at first precisely what problem you're trying to solve. So if you spend a lot of time planning in advance, what you'll end up with is a minutely detailed plan for solving the wrong problem.
With complex, ill-defined problems, you're better off writing a prototype as fast as you can, seeing what turns out to be wrong with it, and then changing your definition of the problem accordingly.
Often the reason programmers are pushed into planning is not that the problem requires it, but that project managers require it. Maybe programmers should give managers an explicit choice: do you want me to solve the problem in the way that will make you feel good, or the way that will yield the best solution?
You can also have a look at Sales Video Cost. Programmer FAQs