In both my sessions with T and marriage counselor (MC), there is some joking and laughter, plus a bit of off-topic talk, mixed in with the seriousness. I find it helps.

Like I think yesterday, T could tell I was a bit overwhelmed with all we've been talking about and I've been dealing with lately, so we really just spent the last 20 minutes of the session chatting about lighter things rather than all the deep stuff. I think it helps our bond. And with MC, it can definitely help lighten the mood or break some tension. Especially as most of his jokes are at his own expense (like making fun of himself).