After all he has been through, and put himself and his family through, David Letterman should be as kind and gracious as possible … as often as possible.

But you can’t teach old CBS Late Show hosts new tricks I suppose.

Letterman and sidekick Paul Shaffer were both unnecessarily rude to Top 10 reader/guest Justin Bieber Thursday.

Letterman dismissed Bieber as “just a kid” and commented about where the superstar singer should throw the newspaper during his route.

Shaffer was worse, drawing a cold reaction from the audience when he commented about Bieber’s height and questioned which gender his new fragrance was for.

Is that any way to treat a guest?

I realize the late night shows are supposed to be comedic and some “making fun of” is OK.

But Letterman seems to be getting more bitter and angry over time.

His never-ending attacks on George W. Bush, nearly three years after he has been out of office, seem desperate and half-baked.

(Letterman’s effusive praise of Barack Obama despite the poor shape of the economy could be another blog entirely)

Time to get some new material Dave, and leave the “kid” alone.

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