Previous ex-presidents are so self aware, there's no way Trump is going to fit in without it feeling awkward.
Clinton will always get the occasional intern scandal thrown at him or his speeches, foundation or Haiti.
Bush however gets away with having killed thousands of Iraqi's for no good reason and plunging much of the world into an economic crisis which he mismanaged so badly that we still suffer from the effects.
Not to mention he put some of the worst people in 'power' and authorized the use of torture and CIA black sites.
But George makes the best jokes. So all is forgiven.
Just look at Obama. He had to clean up most of the mess that Georgie left behind but even he can't be mad at him.