The Trix rabbit is occasionally given a chance to actually try the cereal depending on the outcome of a poll. People vote for him to get it every time, and by now you would think the company would get that people really feel sorry for the guy and hate those greedy kids.
They probably do and know that sympathy for the rabbit makes people remember the commercials more.
Of course the audience is supposed to sympathize with the rabbit—they're supposed to want the cereal as bad as he does.
The message seems to be that the audience is supposed to sympathize with the kids, and feel ridiculously entitled to their cereal, thus becoming more insistent on buying it. Unfortunately, most kids seem to have a moral core that rates "don't be a jackass animal abuser" above "I deserve cereal because the kids become jackass animal abusers for it." Score one for basic human decency.
There have been a small number of ads where he did actually get to eat the cereal — One of them is found Here. In another, he tastes it, goes into his usual "description" monologue, and looks up to see that the bowl is now empty.
One Christmas-themed Cocoa Pebbles commercial ends with the real Santa showing up, and Fred and Barney for a change sharing a bowl of the cereal as friends.
After attempting to get back together with the woman who rejected him for a Swiffer Wet-Jet (buying flowers, dedicating radio songs to her), the broom finally found a new girlfriend - the rake.
A priceless Super Bowl Coke commercial where Macy Balloons of Stewie and Underdog are fighting (aka bumping into each other) in order to get that balloon of a Coke bottle. Eventually, the bottle starts to float away. Both characters turn and see a round shape on the horizon. It's CHARLIEBROWN, who then wins the prize. Watch it here.
Even better, he gets it in full view of a little girl in a blue dress and carrying a football (hint hint).
The story No, I am NOT a Brony, GET ME OUTTA EQUESTRIA! has a Fourth Wall Mail Slot chapter in which BronyWriter pulls the hero, TD Powell back to Earth for the purposes of the Q&A, and while he makes it clear that he'll be sending TD back to Equestria for future chapters, he lets him have his date with his longtime crush Danae first.
In the Space Quest Incinerations fan game, General Bruce Havok, one of the most badass guys in the galaxy, says to Roger Wilco, savior of the galaxy yet perpetual Chew Toy Extraordinaire, that he knows of Roger's heroism and is a big fan. While he did treat Roger like crap earlier, it's largely because it's been many years since Roger's exploits have occurred, and thus Bruce didn't realize he was dealing with that Roger Wilco, and Roger is something of a Jerk Ass when he's not saving the galaxy.
In the Bleach story A Black Heart Ichigo lets Kon takeover his body to get laid while Ichigo takes care of some business.
In Uninvited Guests, after enduring 41 chapters of craziness, Toshiro Hitsugaya is happy when Nanao Ise takes over as his lieutenant, a partner who actually does her job. The narration even points out that the universe may throw you a bone if you work hard and never give up.
MAD's Monroe is occasionally thrown a bone, though they often Yank the Dog's Chain in the very same comic. Two examples:
Getting to make out with his Irish cousin. When his parents find out, they force him to sleep in his roofless tree house in the pouring rain.
Having the school bully steal his date at the cinema, but then getting him to eat a rotten hot dog he found on the floor of The Rocky Horror Picture Show screening next door.
"At Seventeen" by Janis Ian. Inverted in the 1975 pop classic about teenage elitism and being shunned, where the main character — this song's told in first person — not even so much as thrown a bone while all of her popular classmates get all of the attention, accolades and the cream off the crop of boys.
One strip of The Born Loser had the protagonist having a moment of good luck for once. Once.
Howard Finkle, WWE's ring announcer during the 90s and early 2000s, was a Butt Monkey almost any time he had any role in any storyline. However, during a feud between the mutually mulleted X-Pac and Jeff Jarrett, Jarrett bullied Finkle (who was bald) as part of the buildup. After X-Pac won the hair versus hair match, Finkle got to help him shave Jarrett's head.
After years of being the game's Butt Monkey, shown dying in droves in the fluff, getting saddled with unplayable units, and being to some extent incompatible with the current core rules, around the transition to 4th Edition the Imperial Guard finally got a decent codex. Their 5th edition update brought such treats as support gunships and the ability to field more tanks than any other army, pushing the guard into full Who's Laughing Now? territory.
The DarkEldar went over a decade without an update to their extremely limited and increasingly dated model range and notoriously unforgiving rulebook, before finally getting not just a codex packed full of background fluff and viable units, but some of the most detailed models Games Workshop has ever produced.