I don't see why you should feel _obligated_ to give two weeks' notice. Now, it's possible that you want to finish the project you're working on, or for some other reason you don't mind doing it. But, honestly, most of the time if you decided to quit, you're mentally checked out or even worse, hostile toward the company. And it's not as if two weeks is a long time, the employer can't get anyone to replace you that fast anyway. The company often has no obligation to give you any notice either. Now, you don't need to be flip about quitting, you can just say politely that you don't think it's working out for you, that you can't give 2 weeks notice because you need to use the time to take a break before the next gig starts, or that you won't be doing a good enough job or whatever. I think most normal people (co-workers) understand that you have to take care of yourself. That said, in my past I've given up up to six month notice, mostly because I've been lucky to work on great projects and with great people that I didn't want to undermine. But if you're not in that situation, I don't think that there are any _ethical_ considerations in quitting ASAP.