Not Remarketing Properly
Are you selling products and simply remarketing by sending people back to your website? Then you are most likely not remarketing properly and should be using some really cool tools that Google gives you at your disposal.
What you can do to fix it:
You can remarket with product ads so if someone was looking at that stunning black dress on your website, then you can show them more stunning black dresses as they browse the net. What could be more relevant?! Were they searching for accommodation in Bali? Then chances are they are still considering going to Bali so use your cookie pools effectively to target the right people and most importantly, send them to the right place.