I think Max is basically right about this:
Unresolved Sexual Tension is a great way to keep stringing your viewers along from week to week, if you have viewers who get off on that sort of thing, but in the end it’s a cop-out: the characters never talk about their feelings for one another until the last possible moment in the series, which robs us of the chance to see what how their relationship would work – or fail to work.I'd just tweak that terminology a bit to argue that it's really Unacknowledged sexual tension that gets shows in trouble. If characters are aware of an attraction between each other and are resisting it for a good reason, or are working through it (much more to come on all of this later today on Bones), then it's legit. When it's set up though, so sexual tension that's clear there, and is clearly meant to be there, is unacknowledged, it actually does something worse than "[rob] us of the chance to see what how their relationship would work." It asks us to believe that characters we are generally invested in, who are presumably somewhat smart and intuitive, are stupider than we are. We've got to accept the plot arc and loose some respect for characters we've come to care about, or reject the plotting and feel the characters are being ill-used. It's a bad bind to put viewers in, and a recipe for lost audience.