Source: Elementary

[Lance is by himself, staring out into space. He hears footsteps and turns to see Keith, who joins him by the window]

Keith(After a moment of awkward silence): …You can talk about it, you know.

Lance(Suspiciously): Talk about what?

Keith(Fidgeting uncomfortably): About… Look, I know you miss your family and Earth and stuff, and even though I don’t really get it, I know it’s a big deal to you. And you can- you can talk about it. Just, if you need to.

Lance(Mortified): I don’t need to- did Shiro put you up to this? Because you can tell him that this is none of his business and seriously crossing the line-

Keith(Angrily): Shiro didn’t put me up to anything! I was worried about you, all right?

Lance(Storming off): Well it’s none of your business either, so stay out of it!

Keith(Chasing after him): Why is it none of my business? Why is everybody else’s well-being your business, but yours isn’t mine?

Lance(Coming to a halt and glaring at him): For the last time, we’re-

Keith(Crossing his arms): Rivals. Rivals and nothing more.

Lance: Exactly.

Keith: Yeah, well I’ve thought long and hard about that Lance, and after many, many hours, I’ve come to the worst possible realization.  One that might curdle your very blood. You are my friend.