Back on the case

Friday night marks the beginning of “Monk’s” eighth and final season.

And, I’m sorry to say, it’s about time that the USA series signs off.

I’ve never been able to get into the show, and the premiere episode — in which Monk investigates who is stalking one of his favorite childhood stars, just as her tell-all book is about to be released — is a perfect example of why.

Monk, played by actor Tony Shalhoub, goes on and on about the actress (guest star Elizabeth Perkins) and her show, a “Brady Bunch” rip-off called “The Cooper Clan,” in his typically childlike way.

He quotes episodes verbatim, thanks to that obsessive-compulsive nature, and his dense, clueless interactions with the actress herself are just annoying

His behavior, which is really nothing new, makes it hard for me to buy that Monk is a brilliant detective, and that’s always been my problem with the show.

Not to mention that the mysteries are pretty darn predictable, and tonight’s episode is no exception. I’d already figured it out by the first commercial break.

One could level the same charge at “Monk’s” Friday night companion, “Psych,” which kicks off its fourth season at 10 p.m.

The mysteries are never very complicated, but it’s actually fun — and not cloying, like on “Monk” — to watch the shenanigans of fake psychic Shawn (James Roday) and best pal/voice of reason Gus (Dule Hill) as they figure it out.

The banter between Roday and Hill just gets better every season.

Tonight’s episode finds the buddies on a ski vacation in Canada, where Shawn recognizes an international jewel thief (played by Cary Elwes, who will always be “The Princess Bride’s” Westley to me) on the slopes.

At first, it looks like Shawn’s mojo isn’t going to translate up north, as the thief tricks him and makes him look stupid in front of the Canadian authorities. But, rest assured, you know Shawn always gets his man.

Along the way, his will-they-or-won’t-they relationship with cop Juliet (Maggie Lawson) continues.

Last season ended with Juliet asking Shawn out on a date, just as he was rekindling a romance with his former high school crush. Shawn and the crush, Abigail, are now dating, but he continues to share some sweet moments with Juliet.

They will, eventually. Just not right now.

My favorite parts of the episode were the jabs taken at CBS’s “eerily similar” “The Mentalist,” also about a fake psychic and one of last season’s only break-out hits.

Shawn name-checks the popular show when trying to explain his gift and calls it out as a “virtual carbon copy.”

Hey, they say imitation is the sincerest form of flattery — and “Psych” deserves it.