Do not be afraid to make mistakes. Or to make bad design. As my professor said last night, he is more interested in our bad designs because there is something to be learned out of them and they are always more interesting. If you always produce good design it just means that you are creating things you already know how to. Push yourself further, take on the challenge, and grow from the bad and the ugly.
These mistakes happen to now be designs sold at IKEA. See link above.