Taking to heart Thumper's wise words to Bambi (If you can't say somethin' nice, don't say nothin' at all), Bush avoided insulting Obama in his first post-White House speech given to a paying audience in Calgary.
According to CBS News, Bush stated: "I'm not going to spend my time criticizing him. ... He deserves my silence."
(I would have posted a picture of Dubya, but I think you'll have to agree Thumper is way cuter.)