The Argentina international played alongside Balotelli in the side that won the Premier League back in 2012, before the eccentric Italian was sold to AC Milan in January 2013.
Speaking in his new autobiography, which is being serialised by The Mirror, Aguero suggests that Balotelli's controversial behaviour comes from the player's insecurity.
He wrote: "He'd do daft things whenever he felt like it because he thought he could. We'd go out on the training pitch and he'd kick the balls away in different directions just to be silly, or he'd throw cheese over people when he was sat in the dining room.
"I couldn't help but wind him up, calling him silly names and toying with him. But he knew it was because I loved Mario – everyone loved him.
"A lot of his behaviour, I feel, came from a feeling he had that he was somehow different and maybe a little insecure. He used to say that nobody loved him and I'm sure he believed that was true, though it was anything but."
Aguero is currently joint top of the Premier League's scoring charts with nine goals, alongside Chelsea's Diego Costa.