Meta: When a fan at Power Morphicon asked Steve Cardenas (Rocky) if he regretted being written out of the show, he said no. Why? Because he wouldn't have gotten to meet Blake Foster (Justin) otherwise.
Also, the Word of God given around the time of Operation Overdrive that the reason Rita and Zedd were Put on a Bus was because they were taking maternity/paternity leave and wanted to spend as much time as possible with their son.
When Bulk and Skull's invisibility wears off at the end of "Stitch Witchery", Lt. Stone is overjoyed to see them again.