Love him or hate him, Rick Sanchez from Rick and Morty is not someone people want near their children. He's far from the perfect grandfather who will teach his grandkids morals and values. In fact, Rick is quite the opposite.
Still, beneath that abrasive and antisocial carapace, Rick has demonstrated many times throughout the show that he does have a beating heart. He often lets feelings and parental instincts get in the way of his robotic genius. This has led to some polarizing grandpa bonding moments with both Morty and Summer.
GOOD GRANDPA: KEPT SUMMER "SAFE"
It's hard enough to look after one's own underage grandkids while going to different dimensions with them. With Summer in the equation, Rick usually has to be twice as vigilant in protecting both of them in addition to being more tolerant of their incessant complaints.
Luckily, Rick never leaves Summer in a tough spot without help and is concerned enough to keep her safe using his state-of-the-art spaceship/car. It did keep Summer safe all right, in more ways than one, but one can't say the same about her potential assailants.
BAD GRANDPA: LEAVING SUMMER BEHIND
During one of the latest episodes of Rick and Morty, Rick had been unintentionally a bad grandfather to Summer again. It happened in the "Promortyus" episode where both Rick and Morty got enslaved temporarily by face-hugging aliens and managed to get free and come back to Earth.
Turns out they actually brought Summer along prior to that misadventure happening and left her behind the alien-infested planet. Summer only managed to live because the aliens were not that violent.
GOOD GRANDPA: HELPING SUMMER GET REVENGE
Despite Rick mostly having favoritism for Morty over Summer, she still gets appropriate love and care from her grandpa. For Summer, it's more like tough love as she's nearly an adult and this was something Rick taught her in the "Something Ricked This Way Comes" episode.
The "devil" used Summer to make a successful gadget business which is totally not Apple and then abruptly cut her out of it. Rick, being a considerate grandfather, helped Summer move on with bodybuilding and beating up the devil afterward.
BAD GRANDPA: MAKING JERRY AND BETH DIVORCE
Rick has always considered Jerry to be a thorn in his side for most of Season 1 and 2; so he concocted an elaborate plan that would conclude in Beth divorcing his husband. It succeeded and the two of them were divorced for nearly a full season.
What's worse was that Rick thought it was for the best but it clearly affected Morty and Summer (to a certain degree) as well as Beth. Rick did it all because he thought of Jerry as a competition for Beth's affection and wanted the whole household for himself.
GOOD GRANDPA: CRYING OVER HIS MORTY
Morty has often received the shorter end of the stick when it comes to his exploits with Rick. It would appear that Rick doesn't have any guilt or appreciation for Morty even after what he's done for him but this was proven wrong in the "Close Rick-Counters of the Rick Kind" episode.
It's the one with a fake evil Rick and the evil Morty's first appearance. Evil Rick was looking through Rick's memories and inadvertently made the latter recall all his good memories with Morty; this made him tear up a bit, insinuating that he cares and loves his grandson.
BAD GRANDPA: RUINED MORTY'S NETFLIX PITCH
He might not it it, but Rick Sanchez has become somewhat codependent towards Morty for adventures. That's why he feared that Morty having his own dreams and aspirations would cut their "partnership" short. Hence, Rick ruined Morty's biggest chance to have his own big achievement in Season 4, Episode 3.
That achievement was being a writer for a Netflix series about a compelling and twisted heist. To make matters worse, Rick even did it to Morty unknowingly and somehow made his own grandkid lose enthusiasm for his show idea; it was all for the sake of having a gullible and free companion to take on more extradimensional adventures.
GOOD GRANDPA: REVENGE AGAINST KING JELLYBEAN
Another proof that Rick deeply concerns himself with Morty's well-being is during the episode "Meeseeks and Destroy." The two of them set off on their own adventure of Morty's choice while Rick distracts the rest of the family with Meeseeks.
Morty got more than he bargained for when it turned out that King Jellybean, the ruler in the fantasy world they visited, was a pedophile who tried to assault him. Rick caught on what happened quickly and dealt with King Jellybean adequately by vaporizing him.
BAD GRANDPA: MORTY'S MIND-BLOWERS
Speaking of traumatic memories for Morty, turns out Rick could have erased plenty of those at will thanks to his invention, Morty's mind-blowers which is also the title of the episode. It's practically all of Morty's memories-- some of which were erased from his brain.
By doing so, Rick pretty much covered all bad deeds that he did to Morty and made himself look less like a bad guy. Morty also didn't know about this as Rick kept erasing any memory of his regarding the machine.
GOOD GRANDPA: SACRIFICING HIMSELF FOR MORTY
Here's the ultimate evidence that Rick does still care for his grandson: it happened in the episode "A Rickle in Time" where Morty and Summer managed to split their dimension exponentially by being uncertain.
When they were on the verge of fixing it, Morty couldn't make it and would have been erased from existence but Rick sacrificed himself by giving his synchronization collar to Morty. Rick was even prepared to die at that point and wished Morty a good life. At least one of him did, theoretically.
BAD GRANDPA: VAT OF ACID
Finally, here's Rick's latest crime against Morty in the episode aptly titled, "The Vat of Acid Episode." Morty hurt Rick's ego by criticizing one of his ploys so Rick made a device for Morty that would teach him a lesson and subdue him at the same time.
Rick essentially gave Morty the best and the worst he could experience in many lifetimes only to take it all away and make Morty suffer many times over. In the end, Rick revealed that it was all to persuade Morty that his "Vat of Acid" idea, much like all his ideas, is great. He really went that far for his ego.