Nothing Severus said was all that surprising. Besides the fact Severus touched on the issues before, so had pretty much everyone else who compelled Draco to reach out to the Potions Master. Even so, it wasn't easy listening to Severus degrade himself. Draco still thought the man was capable of so much more which may have been the core issue to start. Still, wasn't loving someone believing he or she could be a better person?
He didn't believe refuting Severus' claims would do any good. For starters, he did believe (now) that Severus didn't intend him any harm. For another, he did take Severus at his word. The man had issues just like Draco did and he'd have to work on them; Draco needed to respect the limitations. He'd still hope for the best like some bloody Hufflepuff.
"I'll try to keep that in mind if I get upset about something again," Draco finally said. "I realize my anger didn't help anything. If you're promising to try a bit harder..." He eyed Severus carefully, "I'm promising to try and talk to you calmly." He offered another small smile. "It'll likely be excruciating for us both, yeah?" He held a hand out again in silent offering to Severus. "But I'll never stop caring about you, Sev. It is impossible."