"He's a liar, a cheat, and a thief!", he shot out without any clear reason.  A moment ago, we were just sitting quietly, looking at the gentle waves on the lake.

He carried on grumbling.  I didn't say anything, I just looked at him, and listened.  Teeth clenched - (I'll exclude the expletives) - he followed on, "I really don't like that guy!  I swear, if I had my way... !"  

Remaining silent for a moment longer, I asked, "Want to talk about it?", in the hopes it'd prompt him to provide me a little bit more of a context for this mood shift.  

I had a feeling that I knew already.  Lately, his irritations were directed at Joey, his sister's recently-arrived-on-the-scene boyfriend.  In the last few months, it'd become a pretty common occurrence that whenever the guy was around, a lot of unpleasant, if not downright concerning, things tended to happen.

My feeling was more along the lines of "What now?" than "What's going on?".  To a certain extent, a part of me kind of wished I wouldn't find out, even though I'd just invited Roger to tell me.

Looking at my face, I think my expression might have betrayed to him that I didn't really want to know what Joey had done this time.  He understood that I was enquiring only out of concern for how he's feeling since he was clearly upset.

So, slapping his thighs in response, he smiled, "You know what?  He's not worth it.  Your face says it all!"  He'd said that last part bursting out in laughter. 

Reaching for a beer in the cooler, he handed me one, and we got on with our beautiful day at the lake.  Best buds on a break, the rest could take a hike.