Having played this game for a few minutes, I have some questions:
Does an npc ever walk up to you in a public place, just to chat?
In a conversation, will an npc ever ask you out?
Will a co-worker ever interact with you in a routine work day?
Also, will a random NPC ever visit your home?
1. If you're just moving around the map, I don't think so. I either never made a PC approachable enough or NPCs (those present in the current location) opening up a conversation like you can do with them doesn't happen. Similar events can happen, though.
I feel like a stranger trying to sell drugs to the PC is the most common event, but I assume that's because it can probably trigger almost anywhere on the map. Iirc, you can get the number of those one or two unique NPCs. I don't know if they're only useful for buying drugs, because getting the PC addicted on something quickly leads into an uncontrollable downward spiral.
There are also other random events where the PC can exchange numbers with NPCs, afaik.
2. No. The conversations you can start with NPCs in the area only have two purposes: Exchanging numbers or jumping right to sex. If you've exchanged numbers with an NPC and haven't met them in a while, they may text you to ask for a date/hangout, iirc. I assume those require a certain level of friendship/love to trigger.
3. Yes. The only purpose of those is to exchange numbers, after which you can hang out or date those NPCs like any other regular NPC, afaik.
4. No, but if your PC is spreading pheromones and/or is out late at night, creeps (or perfectly normal people) may try to assault her.