Ask HN: How do you prevent wasting time on the arbitrary details of web design?

I'm extremely detailed when designing user interfaces in order to be pixel perfect. On the surface this seems like a good quality to have, however, I find my self wasting hours on the smallest, most minute details. I also have a hard time making decisions about the layout that are quite arbitrary (meaning either decision results in an acceptable design).

How do you handle these tiny details and decisions? Is this a common problem for designers, or am I simply too indecisive?

Thanks guys.