The Obi-Wannabe

He's older and ostensibly wiser, and more than willing to impart his wisdom upon his children, younger siblings, or other youngster.

There's just one problem: His advice sucks!

Sometimes he's just clueless, but other times, he's intentionally misleading his protege.

The most common subversion of The Obi Wan. Overlaps with Know Nothing Know It All and The Blind Leading the Blind. Oftentimes invokes an Ice Cream Koan. Compare Mission Control Is Off Its Meds.

Anime and Manga

 * Headmaster Cross in Vampire Knight does this to Zero, who usually either shrugs off his advice or Dope Slaps him.
 * Infinite Ryvius actually has two examples, one is Zwei "leader" Lucson, who tries to take command and fails miserably. Heck, arguably every "leader" of the cast fits this to some degree, but a particular example should probably be Julii: Everyone expects her to be a great leader, but she turns out to be (and acknowledges that she is) really bad at it.
 * The spirit of the Harkonnen Cannon in Hellsing tries to give Seras his sagely advice. She chooses to ask if her string of bad luck will continue. His answer? "Yep". He revealed a second later that it was a joke.
 * Brock gives romance advice to several other characters, most notably Ash's Totodile in the Johto saga, Corphish (also Ash's) in the Hoenn saga, and Dawn's Piplup late in the Sinnoh saga.
 * School Rumble has a scene in which Hanai is being trained by an old man, only for the old man to be escorted away by his grandaughter, who tells him "Grandpa! You know you can't go out alone!"
 * Athrun Zala can be seen as a more serious and tragic version of this in Gundam Seed Destiny. The intent was probably to have him be the Older and Wiser mentor to new protagonist Shinn, as happened with Char and Kamille in Zeta Gundam. The only problem is Athrun is still working on his own issues, so most of his interaction with Shinn consists of punching him and calling him an idiot, which only makes Shinn's anger issues and hatred of authority even worse.

Film
"Rick Rambis: Pig Pen, when I want advice about a good Planet of the Apes film or maybe how to get the resin out of my bong I'll come to you ok? But I am not gonna take romantic advice from somebody who cannot spell romantic or advice... or bong."
 * How to Train Your Dragon played this trope hilariously straight with the well-intentioned but verbally awkward Gobber.
 * In Mallrats, Brodie gives advice to TS all the time, but when TS actually takes it... "You're listening to me? To something I said? Jesus, man, hasn't it become abundantly clear during the tenure of our friendship that I don't know shit?"
 * Trojan War: Seth is training Josh in the ways of seducing women. Unfortunately, his advice consists mostly of idiotic pickup lines. After trying them for himself, Josh calls him out, quite aptly stating "You know nothing!"
 * Out Cold:


 * In Hot Tub Time Machine, the mysterious repairman delivers lots of cryptic and ominous-sounding warning, from which the gang infers that doing anything differently will screw up the timeline in unpredictable ways.

Literature

 * Gilderoy Lockhart from Harry Potter.
 * Later, Percy Weasley to Ron.
 * The eponymous character in The Prime of Miss Jean Brodie. She urges one of her "set" into an affair because she (the girl) is beautiful, berates the most intelligent of the girls as being too prosaic, and -- an ardent fan of the fascist Franco -- romanticizes another's brother's involvement in the Spanish Civil War.  Keep this woman away from impressionable youth!

Live Action TV

 * Life With Derek: Derek Venturi is constantly misguiding his younger brother Edwin, encouraging Edwin to be a delinquent like him, giving him faulty social advice, and sometimes intentionally misleading Edwin for his own amusement.
 * Spin City: At the beginning of the season after Mike left, Paul imparted some his wisdom on how to live a celibate lifestyle to Caitlin. Inevitably, she gave up and hopped on a plane to get back with Mike. A later scene where Paul overhears a conversation between Charlie and one of his conquests shows that Paul himself is barely hanging on.
 * Pierce on Community. Even though this is obvious pretty much from the beginning, the other characters still listen to him from time to time, largely because his lackluster knowledge is still the only knowledge about a topic anyone has and because he very occasionally has a good point.
 * In an episode of Hannah Montana, Hannah has found that kids will emulate just about everything she does, and is afraid to ever express her opinions or preferences on television. As such, Robbie Ray enlists Jackson to school her in the fine art of obfuscation. Of course, it backfires horribly, and Hannah ends up delivering the episode's Aesop about being yourself instead.
 * That '70s Show: Hyde has made a sport out of giving his friends faulty advice for the amusement of seeing them make jackasses of themselves. His favorite target is Kelso (who still listens because he's so irremediably stupid,) though he enjoys tormenting Fez almost as much.
 * Colonel Rodney Crittendon from Hogan's Heroes. This re-occuring character was in some ways the Allies answer to the German's Colonel Klink. This British officer would get captured frequently and sent to Stalag 13 with Hogan and his crack team of deep cover saboteurs. He was technically higher ranked then Colonel Hogan (by date of promotion, as Crittendon would frequently remind Hogan) and would often usurp Hogan's Authority. Crittendon was just too incompetent and genre-blind to be anything less then a complete hindrance, though the clever spies would occasionally manage to use his bumbling stupidity to their advantage. What makes him an Obi Wannabe is the endless string of bad ideas and plans he would concoct for the "escape" from the POW camp: Unbeknownst to Crittendon, Hogan and his team have no intention of escaping, as the very premise of the show consists in them using the fact that they were under the supervision of the incompetent Commandant Klink and the incredibly lazy and corruptible Sergeant Shultz to launch various sabotage and subterfuge operations from deep within Nazi territory.
 * Mr. Blanket, Seven Seas High's guidance counselor from The Suite Life On Deck, is himself certifiably insane, distracts people when they examine his credentials, and despite having written a book on them, his methods are questionable at best.
 * The Suite Life of Zack and Cody: When Esteban unexpectedly becomes opulently wealthy, London gives him lessons how to be a snooty, condescending spendthrift. As a result, he finds himself back in the same old rut when his assets are frozen.
 * Probably every single piece of advice given on Strangers With Candy was bad, often spectacularly so, but art teacher Geoffrey Jellineck is the character specifically representing people like this: he desperately wants to be a Psychologist Teacher and is always trying to get his students to confide in him, but he's transparently a clueless narcissist and none of them like him.

Theatre

 * Polonius from Hamlet: half his advice to his son contradicts the other half, and when you look at his actions toward the royal family it's clear he's just trying to ingratiate himself at Hamlet's expense.

Webcomics

 * Tanna of Ears for Elves wants to teach things to younger Elon, but he would rather learn from a "real" warrior.

Western Animation

 * Dad on The Brak Show. Brak is the only character who takes his advice seriously at all.
 * Owl from Bambi. The advice he gives Bambi and his friends is terrible advice to give young animals. Fortunately nature takes over and they ignore his advice.
 * Zapp Brannigan from Futurama, especially when giving Kif love advice.
 * Peter Griffin from Family Guy.