This is what I like. When I start such projects, I am criticised by my peers, told that it is a waste of time and effort, that the best methods and most optimized libraries already exist and that I will never make anything better.

Well, not always the case. Of course I understand the merit of standing on the shoulders of giant(corporation)s, but sometimes you just want to try out something new (to you) just to test your intuition and improve your own perception of existing knowledge.