House had lied.
Put like that, without context, it seemed silly; House lied all the time, to everyone. But never before had he let people spend days thinking he was dying.
Chase didn't know if he could forgive him for this. Worse, he didn't know if he could forgive himself--first for still caring, even after everything House had done to him; second for giving in to the need to show this man how much he did care. He'd just never had the chance to say goodbye to his parents, and he couldn't bear the thought of going through that again. So he'd steeled his nerves and taken a chance. For nothing.
And House had let him.
The best moment he'd had in a very long time had been when he'd noticed that it was not, in fact, cancer. It wasn't just solving the puzzle; it was solving this puzzle, and in a roundabout way saving House's life. Foreman and Cameron had even complimented him on having picked up on the anomaly before they had all piled into Foreman's car and driven as fast as the law would allow to House's flat to share the good news--only to have their high spirits dashed by House's deception. The news had hit Chase with all the force of a personal betrayal.
It didn't even matter that they weren't the intended target of the deception. Once House knew they believed he was dying, he ought to have told them the truth rather than just brushing their concern off with repeated variations on "let's pretend I'm fine". Chase had used "I'm fine" to dismiss warranted, but unwanted, concern too many times himself to be willing to take those words at face value.
And the worst part? That was the relief that underlay the anger and the sense of betrayal. Even now, he couldn't help being happy beyond words that it wasn't true, House didn't have barely a year to live. Not even this latest example of unnecessary cruelty could make him wish House were out of his life, and that was just more proof that his father had been right all those times when he'd called him weak. What greater weakness could there be than continually needing people who, on one hand, couldn't be bothered to tell him they were dying, and on the other, didn't care enough to tell him they weren't?
He wished he were stronger. He wished he could not care for real, rather than merely as words he told himself in a desperate effort to make the disappointments in his life hurt less. He wished he could be like Foreman, and brush this aside in disgust, or Cameron, and have a faith in people that was in the long run undiminished by their actions. But he wasn't, and he couldn't help taking things like this personally, no matter how much he'd come to expect them.
Not that he'd expected even House to lie about brain cancer. Saying he didn't have it when he did, perhaps, but lying about having it when he didn't? Who could possibly anticipate that, even from someone like House? Regardless, Chase knew all about disappointments, and he hated the fact that he hadn't grown immune to them.
He wasn't even immune to the disappointment he felt in himself when he walked into work that morning and his first reaction to seeing House through the glass wall of his office was relief that none of it had been true.