I Should Have Done This Years Ago

A Stock Phrase wherein a character acknowledges a past missed opportunity just as they are about to do what they were unable to (or chose not to) all those years ago. Often, the character spared a foe's life in the past and has since come to regret letting the Ungrateful Bastard live, in which case the phrase usually comes during a Sword Over Head moment and may be accompanied by Prepare to Die. Bonus points if the character in question is a villain who foolishly killed one of his enemies in the Backstory but left their child, now The Hero, alive out of scorn, or a Mentor who couldn't bring himself to kill his beloved pupil, now the Big Bad, even when their Omnicidal Maniac tendencies became apparent.

Note that the phrase may be used in regards to plenty of things other than murder: a risk not taken, a path not followed, a high school sweetheart not smooched - any of these may provoke the phrase years later, optionally accompanied by a wistful expression and/or a tear in the eye.

This trope can also appear in more disguised forms, without having to invoke the Stock Phrase. "I have a certain phone call to make"/"there's a family waiting for me"/"I just realised I need to visit an old friend"/etc. are all stock sentences that stem directly from this concept.

Loosely related to I Always Wanted to Say That.

Film
"Mark Darcy: I should have done this years ago. Daniel Cleaver: Done what? Mark Darcy: This. [Punches Cleaver, hard]"
 * Bridget Jones' Diary

"Sam: Austin? What are you doing? Austin: Something I should have done a long time ago. [he kisses her]"
 * A Cinderella Story

"General Mandible: Cutter, what are you doing? Colonel Cutter: Something I should have done, a long time ago. [extends his hand to the worker ants] This is for the good of the colony, sir."
 * Antz

"Johnny Nelson: I'm going to do what I should have done a long time ago...I'm going to round up those crooks!"
 * Call of the Prairie (1936)


 * A History of Violence:

"Jeremy: I quit. [snip various protests] No, no. I need to thank you. For giving me the courage to do what I should have done a long time ago."
 * Passport To Paris

Literature

 * Eoin Colfer's The Wish List is basically about an old guy fulfilling this trope.
 * Early in Stephen King's The Stand, Frannie Goldsmith's father touches on this trope when he finally puts his foot down about his wife living in, essentially, a shrine for their dead son.

Live-Action TV
"The Doctor: Jackie Tyler, do as I say! GO! AND CHECK! THE DOORS! [she does] Should've done that ages back."
 * The Doctor Who episode "Father's Day"

"Riker: I think I'm ready to talk to Captain Picard. Should have done it a long time ago."
 * Star Trek: Enterprise episode "These Are the Voyages..."

"Gil: Hey there son! Jimmy: What're you doing here? Gil: Something I should have done a long time ago! [wraps his arms around Jimmy and gives him a big hug]. Jimmy: What? Molest me?"
 * Greg the Bunny

"Jen: I should have told you this a long time ago. I love you!"
 * Power Rangers Time Force episode "The End of Time: Part 3"

""I should have told you when I first found out, but I didn't have the guts.""
 * Star Trek: The Next Generation, final episode: Picard joins the bridge officers' poker game at the end, and is offered to deal. He says this line, to which Troi says 'You were always welcome.'
 * Battlestar Galactica: Colonel Tigh in "Revelations".

Newspaper Comics

 * Calvin and Hobbes: Calvin's dad uses the "Should have thought of this years ago" variation in one bedtime story strip: the story is about a disembodied hand that goes around strangling people and was never found, so to this day it could be anywheOHMIGOD IT'S GOT ME!!!! With Calvin out cold, his dad says the above line.

Video Games
"Gleeman Vox: Now I'm going to do what I should have done a long time ago... I'm going to give DreadZone fans the finale they always wanted... It's a little one act play I like to call... Death... of A Lombax."
 * Ratchet: Deadlocked


 * In Mass Effect 2, you have a second encounter with the annoying reporter you met in the first game. If you didn't punch her then and do the second time, you say "I should have done that the first time we met."
 * At the end of Mega Man 7, Mega Man is sick of fighting Dr. Wily over and over again only for him to escape and try again to take over the world, so he delivers this line and starts charging his Arm Cannon. However, he's stopped by a "Three Laws"-Compliant and Bass rescues Wily.

Web Animation

 * "I shoulda done this like a million years ago!"

Western Animation
"Lois Griffin: Wha? What are you doing with a gun? Stewie Griffin: Something I should have done a very long time ago! [shoots Lois]"
 * Family Guy

"Bart: Well, Pop, what are you gonna do? Homer: Something I should have done a long time ago! [long pause] Marge: You don't know, do you? Homer: No, ma'am."
 * Lampshaded by The Simpsons. Marge writes a novel with the main cast as expies of herself, Homer and Flanders. Events play out in a way which mirrors the novel, resulting in Homer confronting Flanders on a cliff (in the book, the expies fall off a cliff in a fight over expy Marge). Homer cites the phrase..
 * Episode "Homer Goes to College"

"[Homer pulls up an axe] Marge: Homer, what are you doing? Homer: Something I should have done a long time ago. [turns on Bart with his axe] I'll teach you to mess with my machine! Bart: [begins screaming and running while Homer chases him] Homer: I'm gonna chop you good!"
 * Episode "Treehouse of Horror VIII"


 * In Disney's The Hunchback of Notre Dame, Frollo, after explaining that Quasimodo's mom didn't actually abandon him (which is what he had told him his entire life), he says the famous line, "And now, I'm going to do what I should have done....TWENTY YEARS AGO!!!" and proceeds to
 * One episode of SpongeBob SquarePants parodies this trope. When Spongebob is in Mr. Krabs's jelly processing plant, he picks up a wrench, and when asked what he is doing, he says, "Something that should have been done a long time ago!"... and then proceeds to fix a loose nut.

Real Life

 * Napoleon Bonaparte said "I should have shot him" about Charles Maurice de Talleyrand-Périgord, the Prime Minster of France. Given Talleyrand's record, he probably should have.