In SharePoint 2013 / SharePoint online when you create a new list or library it automatically appears under a ‘Recent’ section.
There are multiple ways to hide this from sandboxed solutions to Jquery etc, however the cleanest way for me to remove / hide this is by using OOTB features & in this case audience targeting.
1) Create a new SharePoint group called ‘Hide recent’ or anything you want
2) Remove the creator from this group & do no add anyone to it
3) Now go to the navigation settings of the site in question, edit ‘Recent’ and add your new group as the target audience
Nice clean & OOTB solution to this annoyance for many.