Or, as a single or couple there, you are inserted in a larger group that is traveling together. That situation has been hit or miss for us on a few occasions.
odd as, as when it’s applicable, the greeter is very clear that you will be assigned to a table with another party.
like the OP, have moonlighted as a bartender, have been told I can carry on a conversation with a rock. However, I also can read cues and, in that sort of instance, wait for the other part to engage past the usual brief responsive greeting.
specifically at Oga’s, upon extending a mere hello when joining both standing & sitting tables; have encountered people respond by giving the coldest of shoulders. once, a group summoned the server complaining we were intruding.

Appears we were not the droids they were looking for. To his credit, the served managed to keep a straight face & we got the 2nd round on the house.
it’s the only place onsite at WDW that I’ve run into anything like that. We visit often, have only had these rare, awkward moments. However, felt it prudent to mention the possibility for solo travelers. That sort of thing generally rolls off my back You have to laugh that sort of ignorant behavior off, as disney does attract it’s share of people who are obviously out of their element interacting with “strangers”.