No, of course not, you don't abandon your idea. You do make sure that you don't use any trademarks of copy or any copyrighted material without permission. But think about it -- where would the western world be right now if nobody ever imitated anybody else's good idea?

It's not unethical and not stealing as long as you respect intellectual property. And you don't have to be the first to be the best. Sometimes being second or third is even better.

Tim