I am not sure if this has been mentioned yet.
Currently your outstanding tasks will show anything that you have the ability to change, this means that there is WAY too many items in the list then is relevant.
My solution would be to allow a script to run (on item creation although doesn’t really matter) that would take the information from a user pick list field (let’s call it Assigned to) and add that person to the additional owners of the item.
Then in the security settings do not give your users access to see items owned by others and hence leaving you with an outstanding items list that is relevant to you not your entire team.
I understand that I could just add them into the additional owners manually however this is extremely frustrating as there is nothing to prompt you to do so and is often forgotten, if it is a field then I can make it required.