You were tired, but mostly, angry. The unsub was not giving you anything, nor any of the members of the team, and everyone here knew that he still had victims, alive, somewhere. Meaning you guys were losing time.
You weren't really someone who got angry often, Spencer never really saw you like this before, which meant he was worried about you. But you were frustrated, seeing red, feeling guilty — you were a trained BAU agent, for heaven's sake, why couldn't you make this man talk? Ugh.
Right, you needed a break. You walked outside the briefing room, where the whole team was, talking about strategies, about how to break the unsub, how to locate his victims— Air, you needed air. So you walked outside the briefing room into the bullpen, and sat down on your desk for a moment. But you didn't notice Spencer that came up behind you, and you literally threw your paper weight on the wall out of spite, frustration, everything. It hit Spencer right on the forehead, and you only turned to look over your shoulder when you heard the 'thunk' of it hitting his bones in his head.
Like the day wasn't bad enough already. You shifted on the desk and ran towards him, both of your hands lingering, almost touching his face, almost cupping it. Your eyes searched his face, worried — you were crying, but you didn't even register it. It was all the anger, the stress, and you had hurt Spencer now. It wasn't bleeding, thankfully, but oh... There was a red bump right there on his forehead that was certainly going to grow purple. It looked like it hurt.
"I'm so sorry—" You started. "I'm sorry, I didn't mean—"
Spencer knew. Of course he did. The man knew everything about you — he loved you, even though he hadn't told you.
"I know." Spencer said, his hands coming to rest on your shoulders. "I know. I did walk in unnanounced and without making a noise."
Still. You had hurt him.