Meddling Parents

They fuck you up, your mum and dad.
They may not mean to, but they do.
They fill you with the faults they had
And add some extra, just for you.

— Philip Larkin, This Be The Verse

Older adults who are far too eager to be involved in their grown children's lives, give them advice on how they should live, etc. Often they will try to take care of their child's problems for them, especially when it comes to educational opportunities and advancement. In most cases, their efforts may be more detrimental to their their child than beneficial in the long run. They view this as "helping" and can't imagine why anyone wouldn't want help, and become offended if their help is rejected. May be especially critical of their son-in-law/daughter-in-law.

In real life, parents can act like this as well, making this trope an example of Truth in Television. These parents are called "helicopter parents" due to their tendency to "hover" over their children, and are the bane of every teacher and admissions officer on the planet. Helicopter parents can effectively be put in these categories:

The Agent, aka the JetRanger : Having an Agent helicopter parent is like having Max Clifford working for you round the clock-for free. They operate like a footballer's agent: fixing deals, arranging contracts, smoothing out local difficulties. It's the Agent's job to represent his or her client at events which, for whatever reason, the client feels are simply too tedious to attend. Specializes in nimble, agile bargains and deals.

The Banker, aka The Halo: Accessible online, face-to-face or via a personal hotline, the Banker is unique in the world of financial services for charging no APR, asking few if any questions, expecting no collateral, and being psychologically inclined to say "yes" no matter how illogical or poorly articulated the request. The Banker is also resigned to never seeing loans repaid. That's assuming they don't just do the shopping directly, and just show up with the gear.

The White Knight, aka The Dolphin: Imbued with an almost semi-mythical status, the White Knight parent appears at little to no notice to resolve awkward situations. Once resolved, the White Knight will fade anonymously into the background. Intervention is accomplished silently and with minimum fuss.

The Bodyguard, aka The Hind: The primary function of the Bodyguard is to protect the client from a range of embarrassing social situations - such as cancelling appointments and soaking up complaints on behalf of their client. Particularly skilled in constructing elaborate excuses. When not protecting life, limb and reputation, doubles up as a chauffeur and personal assistant.

The Black Hawk: Named after the military helicopter that specializes in clearing the way for delivering elite troops. Dreaded by teachers and educational administrators (Especially the sadistic ones), the Black Hawk is unique among helicopter parents due to their willingness to go to any lengths - legal or illegal - to give their offspring a positional advantage over any competition. Particularly lethal when elected to parent-teacher associations. Lack of a civilian name emphasizes their warlike nature: always on the attack.

See also Evil Matriarch and My Beloved Smother. I Want Grandkids is usually a subtrope. Compare with Anticlimactic Parent, or Knight Templar Parent for still-actually-kids kids. The Stage Mom and her spear counterpart are a specialized and particularly obnoxious Sub-Trope.

Basically the family version of Executive Meddling.

Examples of Meddling Parents include:

Film

Every mother depicted in Stick It was The Agent variation of helicopter parent; and some were a particularly abusive twist on that—more focused on their daughter's gymnastic success than in their happiness or mental well-being.
In August Rush Lyla's father is so obsessed with making sure she is a successful violinist that he intentionally separated her from her son by forging her name on the adoption certificate and told her that the baby died. He does redeem himself by telling her eventually what he had done although he kept the secret for 11 years, making him a classic "Black Hawk" parent.
Sheelah Sugrue in Darby O Gill and The Little People.

Literature

Moomin mama and Moomin Papa in The Moomins are an inversion of this. They let their son go comet hunting with only a flask of raspberry juice and a money grabbing, over-egoed mouse kangaroo for company.
The parents of Overload in the Whateley Universe are so much this trope that he's become a bitter, depressed alcoholic. And he's only 15 years old!
In the Dubliners short story "A Mother", the eponymous character behaves more like her daughter's agent than a parent.

Live Action TV

Richard and Emily Gilmore in Gilmore Girls are constantly trying to "help" their daughter and granddaughter—or, if you prefer Lorelei's interpretation, control their lives and suppress their free will. They are, in fact, so manipulative that it is often bordering on impossible to believe that they legitimately care at all, and aren't just trying to ensure the outcome that will bring the least disrepute to the family name.
Marie Barone, Raymond's mother on Everybody Loves Raymond. Frank, his dad, not so much.
Jerry's parents on Seinfeld.

I'm used to a 1200 mile buffer zone. I can't handle this. Plus I got the dinners, I got the pop ins. They pop in! It's brutal!

Bert and Sylvia Buchman on Mad About You.
Grandma Ida on Malcolm in the Middle.
Caleb in The OC.
Mother Jefferson in The Jeffersons.
Endora [and the rest of Samantha's family, really] in Bewitched.
Rita's mother on Dexter
Sarah Connor of the Terminator franchise, most notably the The Sarah Connor Chronicles is definite Black Hawk. It's justified in that her son grows up to save all of humanity.
Parental Control.
Angela Petrelli of Heroes. Willing to let one son blow up New York so her other son could become President one day. And that's just Season One.

Newspaper Comics

John and Elly Patterson of For Better or For Worse exhibited these tendencies, big-time, as the strip progressed.

Theater

Logainne's fathers in The 25th Annual Putnam County Spelling Bee are obsessed with forcing her success in both the bee and life in general. One goes as far as to sabotage another contestant.

Video Games

Morgan Fey of Ace Attorney really, really wants her daughter Pearl to be the next Kurain Master. To the point of tricking Pearl into nearly murdering the contender to the position by asking her to channel the vengeful spirit of Morgan's other daughter Dahlia, who would then kill Maya using Pearl's body. It's unclear if Pearl ever really understands what's going on, and given her young age it's probably better if she doesn't.

Western Animation

In Daria, Helen Morgendorffer constantly tries to feel she is meaningfully engaged with her children when not at work, regardless of whether her daughters want it or not. However, the trope occasionally subverted, with her help being appreciated, whether it is helping Daria with a story project or defending her in a legal matter.

Real Life

This is part of the stereotype of the Jewish mother-in-law, who usually dotes on her son but constantly criticizes him and outright loathes her daughter-in-law.
- Of course, the stereotype has spread to Italian mothers (or at least Italian-American) and Greek mothers and mothers in the Deep South... let's just say that the stereotype is universal (whether or not it's Truth in Television depends.)
Stephenie Meyer, Author of Twilight has a meddling brother! Dear Seth Morgan controls which e-mails Stephenie sees and he won't let his dear sister Read petition from her fans, Urging her to continue writing despite the leaking of "Midnight Sun" He's pretty much regarded as an asshole by both rabid fans AND antis!