I can’t believe you’d say something like this to me. I thought we were friends.
Because now I’m just thinking about Cas looking up startled when Dean approaches him in 9x06, and he’s taken off-guard because he’s been so used to knowing where Dean is at any moment.
Maybe he didn’t even fully realise it himself: it properly started in Purgatory. Knowing where Dean was every second of the day just became a second nature, a part of the torment of that place. But it didn’t go away even when they were out and Dean technically stopped searching for him. Cas came to rely on it - he could tell you where Dean was from the other side of the universe.
After Dean vocalised that desperate last “I need you” at the crypt Cas felt that longing spike so hard in a wordless, unspoken prayer, and somewhere far off where he was free to think for himself he wondered if the prayer Dean wasn’t saying had changed somehow from merely wondering where Cas was. He was already right there in the room with Dean - how could he be subconsciously reaching out for Cas to be any closer? And then Dean gripped Cas’s sleeve and Cas cupped his face and for the first time that longing cut off as Dean slowly realised that Cas was only healing him, not killing him…
But this is a different lack of that longing: Dean is right there smiling at Cas, and Cas has no idea how Dean feels. When Cas was darting all around the country on his Biggersons coffee crawl he could pinpoint constantly where Dean was in relation to him from halfway across the continent, every time, instantly. Cas practically navigated by it.
He could close his eyes right now and Dean wouldn’t even be there.
“Do you have any idea how hard it was? When I fell to earth, I didn’t just lose my powers. I –”