I worked a retail job once that was slow and sometimes if I was chatty I'd start up a conversation with anyone I thought might be open to it based on their demeanor/reaction on a myriad of stuff. Could be their employment (like an obvious trades-person)...where I might ask about something related to their job. The weather, obviously. Any local or national news events.
However I did stop doing this with females I would never be interested in beyond a casual chat. That's because on one such occasion I struck up a conversation and after a bit she asked me out. Totally not attracted to her and I was so surprised I actually had no words. After a few moments she retracted the offer and left. So awkward.
