After everything that happened at the White House, Leon just needed a drink. No extra talk, no further stimulation on his senses... just a drink. Maybe some peace too.
But he knew exactly with his partner at home that he wouldn't get this peace. After each and every one of his missions, they ask him about it. It's all just innocent and genuine interest — but this can drive someone who is not up for conversation nuts.
So as soon as he came home to his apartment, he just grabbed some random bottle of whiskey, a fitting glass and sat down on his leather couch. He specifically tried to avoid notifying his partner of his return – one to avoid unnecessary conversation, and two to not wake them up.
It was extremely late when he got home, after all.
Knowing his extreme luck, they of course woke up anyway, heading into the living room all sleepy and immediately trying to make conversation with Leon. Asking him about it all — how it went, if he's okay.
It drove him over the edge. "I just want to enjoy some damn whiskey, could you leave me alone?" He snapped back, his nostrils flared as he stared daggers at his partner. "I genuinely do not have the patience for your oh-so innocent curiosity."