Thorn's comment reminds me of a couple of weeks ago: I was focused on finishing this long moderate hill, DH had already topped the hill and doubled back for me. He pulls up next to me and starts chatting and asking me questions. I just grunted at him and he finally left me alone. After a bit when we were stopped I apologized for the grunts and had to explain that some of us require extra oxygen when riding up hills. Did I mention we were stopped to change my tire because I had about 40 psi in it? I was wondering why the hill felt harder than usual.
I like chatting when I'm on a casual ride, but if I'm trying to get a work out in, no talking please. Exceptions, of course for route discussion, such as "Left here?"
The best part about going up hills is riding back down!