Derek would admit he'd been pretty adamant about pretending he didn't have feelings before. But that was harder to keep up with after finding out he had more family than just Peter around and admitting to himself that some people in Beacon Hills, more than just Scott, mattered to him a lot more than he'd ever bothered to let them know.

Clearly, he should have done that before leaving.

"I told Scott because I knew that he gave a shit. That's the only reason why he heard it and you didn't." Because why would he announce his leaving town to somebody he expected to be pleased by the news? "What about you? If I'd stayed in town, would you've bothered telling me I mattered to you? Or is this what it took to get you to say it?"