Originally Posted by duwin2008
this is the list of items that are not ego.
i got the achievement without getting this list
Some of the Ego objects, like toilets for example, have multiple appearances; you just have to interact with one of them! If you missed all the toilets prior to the Burning Bush chapter, then using the toilet in Burning Bush will give you the Ego boost! Or if you used the toilet in Rude Awakening (like me) then there is no need to use any toilets afterwards.
EDIT: Nice guide, bennifer3000!