Dragon Ball Super introduced various elements of the world that provided a more cosmic and divine scale to its characters and power system. From God Ki, the angels of the Omniverse, and the Gods of Destruction. One such God of Destruction is iconic and the most well known in the fan base for his personality and waves as the introduction to the concept of stronger opponents for Goku and Vegeta to surpass. Beerus, the God of Destruction of Universe 7, is usually the first character that comes to mind when one considers his appearance as a hairless cat as well as his behavioral lazy patterns. However, another thing related to him is his potential to be a threatening enemy as shown during his first appearance in the Dragon Ball Z: Battle of Gods movie. Which begs the question of why he could be a threat in the future, as well as how easy it could be to turn him.
As many fans of the show are aware, Beerus as an individual is fickle, somewhat ill-tempered, and yet very clever enough when the situation calls for it, much like a cat. Even so, his first time ever coming to Earth was in search of the Super Saiyan God he had heard of in his dreams. While he was pleasantly distracted by the festivities and the taste of Earth's delicacies, it didn't take much of a disagreement between him and Majin Buu to incentivize his anger and short temper. If it hadn't been for the Z-Warriors, Vegeta, and eventually Goku, Beerus would have been dissatisfied and outright destroyed the Earth without a thought or even any struggle. Despite that, with recent developments as well as his somewhat neutral but agreeable terms with the Earth; many wonder what reasons would he have for destroying it now.
Beerus' Outlook
It certainly can be said that Beerus is a lazy God Of Destruction, as we can see in the future episodes of the series. Of course, compared to most other characters he's also the most easily swayed when it comes to food, along with his assistant Whis. It's the one character trait that has so far been exploited by many characters on Earth, notably Bulma, to convince Beerus to consider tasks that he would otherwise not have even bother considering. However, that doesn't mean he's necessarily on their side to begin with.
After all, Beerus doesn't have to answer to anybody in the mortal realm other than Whis or the greater powers in the Dragon Ball Omniverse, that being the Grand Priest and Zeno. On top of that, his personality even as of now is fickle and easy to change so long as he finds some use in having Goku and Vegeta around. Along with that, Beerus considers Earth to be his main source of food and taste, which is one of the few reasons he has bothered to leave it undestroyed and safe for now. There is no guarantee that Beerus will leave the Earth alone and safe if he isn't satisfied or given enough reason to. Goku and Vegeta weren't strong enough at the time to defeat Beerus one-on-one, and until we have a rematch from them, it isn't likely we will get a chance to see whether they have grown strong enough to do so or not.
How Long Until It Happens?
With recent developments regarding the Dragon Ball Super Manga as well as the movies, it seems that Beerus and Whis will be far more involved in the training and development of Goku and Vegeta, and most recently even Broly. However, while the Manga has different reasons for their training the movies have provided some foreboding understanding of Beerus' place in the story as well as the leading question on everyone's minds. When can the audience, and the characters expect for Beerus to turn on Earth and become a huge threat again? It only seems to be a fitting arc to explore once Goku and Vegeta achieve new strengths that either put them on Beerus' level or beyond him. After all, whether this amicable dynamic between the God of Destruction and the warriors of Earth will last or not is all up to Akira Toriyama's discretion and Toei's execution once it is animated.
Still, the fans may or may not be too happy to see such a possible twist of events in the future, as this could be seen as a betrayal of a slow-burn character arc for Beerus. The case could be made that Beerus has grown to have a soft-spot for Earth and is less willing to destroy it out of anything like petty anger. While such a theory is plausible and fair, there isn't a guarantee that it will happen. Dragon Ball Super has shown us the extent and cosmic perspective these Gods have in comparison to humans and mortals, and it isn't hard to say that if Beerus was forced to or chose to; he could destroy Earth with the flick of a finger and with no conscience about it. Beerus as a character was written this way from the start, and much like a cat at times, can have varying moods which dictates his actions as opposed to reason or simple persuasion. Dragon Ball Super succeeded in that regard, creating a truly neutral character not evil or good, but rather an obstacle that could potentially become the main threat if the warriors of Earth aren't careful.