Not everyone who visits your site should be remarketed to – or at lest some users make more sense than others – and the optimal remarketing strategy should be to only market to those with the most potential to come back and convert as a result of you paying to advertise to them.

Its easy to juice the numbers so that they look better by only targeting, and taking credit for, visitors that are highly motivated and by not targeting visitors that are very unmotivated. Visitors that are highly motivated, like visitors that have multiple items in their cart are probably going to come back and buy without any nudging from display ads. Not targeting the unmotivated, like anyone who bounces from the site will increase ROI because those people are probably are not very interested anyway.
In between is the sweet spot: remarketing to those who are interested enough to engage on the site but just not quite enough so that its obvious that they are planning on coming back and purchasing.

Google adwords does allow for this customization to a point. You can create custom combinations that exclude people who bounce and exclude people who have added items to their cart. Unfortunately you can’t get so granular as to exclude based on the number of pages they visited. But when talking to any other vendors you should be wary of these strategies that try to inflate how well the campaign looks like its doing.