Shaquille O’Neal sat down with David Letterman last night, and confirmed what we already knew: He’s having a blast in Boston. The Celtics big man, who last appeared on Letterman’s show a decade ago, said he’s been treated “fabulous’’ by C’s fans. “It’s interesting how life works because when you were in Los Angeles, they hated you in Boston, didn’t they?’’ said Dave. “They sure did,’’ replied Shaq. “I live in a small town called Sudbury. I signed kind of late, so I really didn’t have a chance to find a house, so I went on Google and put ‘big house outside of Boston,’ and I found this big 10-acre farmhouse, so . . . I love it. Wild turkeys, wild foxes, wild bears.’’ The Big Shamrock also gave shout-outs to Kevin Garnett, calling KG “the funniest guy in Boston,’’ and to Hall of Famer Bill Russell, whom Shaq said he would choose over all others to start a franchise.