i keep it on the road, avoid MUP's... too many joggers, kids on bikes and older folks walking...

as for the situation of etiquette when you say you pull up to someone who isn't in the mood to chat, I mean... handle it as you would in any other situation...

let's say you sit next to a rando person at the bar and they're not in the mood to talk after you say hello... kindly take the hint and mind your own.... if you keep trying to press them for some conversation, they might find you pushy, and haul off and give you a nice right hook. By the same token, they may just move away further down the bar, or just keep acting like you don't exist.

I guess it is kind of weird that people on a MUP wouldn't want to chat; most people I see on those are absolutely being casual, but whatev's... they don't say hello back, just pass them, move back to the right and accelerate... they'll either fall a lil' behind you or in turn pass you. Not a really big deal.