Bruce aka Yellow Bee

Its really hard to say who is Bruce for me. He is my inspiration for training, for approaching life and many other things. But sometimes I feel like I'm closed and I can't create anything good. Today was that day. I've spent over five hours doing this simple vector poster. Most problematic for me was his mouth. I just couldn't get it done well. I've tried hundreds combinations changing colors, shape, shading, highlights, position, everything. I was about to give up already but finally I've managed to do something acceptable. I'm not proud of this mouth but now i think i can't draw anything better. I will try to improve this next time. 
One good thing learned from Bruce. No matter what, never give up. And I didn't. 
Any advices?

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