Oh man, Im not saying that other designs suck or are useless here, Im just saying that this design under 2. is the best looking for the tshirt, well designed, good slogan, and the cow on the back is like cherry on-top :)
Also, I can only dream about making tshirts like you, or like him, or any other great designer here :)
So, dont stop, and keep on making great designs! Designs arent always accepted by people for various reasons, not getting the idea of its design, and other BS...
Never give up!
I was joking!!! :-P
And I see you've changed the design you like ;-)
I have to say that 2 fits in well with the designs already in the shop... in my 'defence' I did mine a long time back before there were any official ones and then was too lazy to do a new one (excuses, excuses!)