It was something he'd been anticipating for weeks. Augustus viewed the wedding as an invaluable opportunity to earn more political capital, to develop relationships and build new ones. He had planned for many different scenarios and potential challenges. His preparations didn't include a relatively uneventful event. The chatter of his peers didn't belie the kind of transformational moment he had idealized. It was more like everyone was settling into a new complacency, taking for granted a new paradigm of leadership. As it turned out, the initial instability from the old King's disappearance seemed to be an isolated event. That meant Pompey had handled the situation skillfully.

But it also meant hours of inanity with other noble born subjects. A lot of it consisted of the typical barbs and boasts that one would expect. They never tired of subtly reminding him of his family's own misfortunes, to which Augustus had largely grown inured. A few times, his lack of interest and general aloofness caused insult without him intending any, which didn't hurt his standing (given the relative obscurity of those he encountered) so much as it saved him time.

So when he saw the elderly man lurching toward him, Augustus had mixed emotions. He obviously felt apprehensive about the letter he'd been given, and about what Catullus had in store for him in general, but if it would deliver him from the disappointment of the wedding party and engage his mind in something more rousing, he would be grateful. His relief didn't last long when Catullus seemed to almost lurch into him, and the cage caused him to reflexively take a step backward, nearly spilling wine from the goblet he'd been grasping a little too carelessly for sudden movement. Politely, he attempted to speak: "Good evening Mage-" but was cut off by the barrage of abuse that seemed to come from nowhere. The first issue, he attempted to address by saying, "I'm terribly so-" but was cut off again. After two more attempts, he gave up and kept his mouth shut, nodding furiously at each subsequent volley. His ears burned with embarrassment when he was finally notified that it was because of poor hearing that his attempts were in vain--he might as well have been talking to himself. 
Then Catullus began to walk off with very little warning, leaving Augustus with the task of rushing after him. It proved to be an overreaction, given Catullus' painfully slow gait. Without the natural graces his upbringing had instilled in him, his sudden move might have sent him crashing into the man ahead of him. But of course it didn't and, to his credit, he still didn't spill his wine either.