When I build things I'm never really finished with some. I work in iterations. That's both a good and a bad thing. Let's talk about the good things first, because they outweigh the bad things!
The good in iterations
Working agile and iterations go hand in hand. Actually without iterating over an idea, a project or product there'd be no agility. In the old-fashioned way of working ‒ say waterfall ‒ there was not much chance of reacting to changing demands, because nearly everything was set in stone. In fact iterations where still possible. But either only after the current job was actually finished or by risking the deadline - and putting more workload on the team. Or if someone had planned a lot of buffer time. Time that went into the client's bill. Not an ideal scenario.
Being backed by agile methodologies, working in iterations means you can transform your vision into reality in a much shorter time. Usually, you'd release the first iteration as an MVP (Minimum Viable Product), as soon as possible. Keeping the User Experience in mind a certain degree of lovability, usefulness and usability has to be there for the MVP to work. That's why you'll find more and more people talking about an MLP (Minimum Lovable Product) instead which excels at a core functionality.
With that step done, the iterative cycle begins. You'd review your work questioning if it's initial idea (or the hypotheses behind it) are still valid, you'd listen to the voice of the customers/ users to gain insights and you'd have a look at data you've gathered by web analytics or other tools. The next steps might be enhancing the existing core functionality and testing new features with a limited user base if that's feasible. Iterations might also include running A/B- or multivariate tests to find out where the product is lacking traction and unused potentials. And you can use the time to aquire users.
Letting an idea go
Because of the iterative approach you're not locked in into the product. Yes, you might've fallen in love with the idea behind it. But, if you find that the product does not bring the success you've aimed for, it's much cheaper and less painful to let it go and start over with the next idea.
The bad in iterations
Is there anything bad about working in iterations at all? Well, you could say that it prolongs the time that work is being put into a project, because there is always something to do.