Originally Posted by Phosphorblind
It is important to know how to create everything yourself from scratch.
Again, since when? 'Why reinvent the wheel?' You should understand how things should be used and how they work but you don't have to recreate everything you use.
Libraries like the .NET framework, C++ Standard Library exist because they were written by many experts of the language and domain which are faster and more robust then what the average programmer can do.
When you drive a car, do you need to know how it works under the bonnet? When you use a computer, do you need to know how the components interact with each other? When you use PHP, do you need to know how the server works that parses it?