With the insincere 'small talk' I've struggled with being on the receiving end of this over the years. I'm quite literal, if somebody says "Hey let's do XYZ!" in my mind it's a done deal, even if to them it's just an idea, or passing small talk. This means I've been frequently disappointed in my life.
One friend in particular I met nearly 18 months ago now I see a lot of, but it took me 6 months to realise that when she said "And we'll definitely do something next Friday!" or "This was great! Let's make it a regular thing each week!" that this didn't mean we had a commitment. Sometimes I wouldn't hear from her about it at all, other times I would reach out to her but she couldn't because she would have family coming to town, or plans with friends, or an appointment somewhere. I don't think she is the kind of person who would keep me as "back up" for if nothing better came along - I think she just genuinely wasn't planning ahead, and in that moment
she sincerely did want to see me again. And I do still see her regularly so it doesn't bother me too much.... now that I know not to hold my time free for her unless we have definite plans. To be honest, it still annoys me a teeny bit - if you don't want to commit to anything, keep it vague! No need to say anything about meeting up!
Even last Sunday night when we were texting each other she said "And we'll definitely see you during the week!" to which I thought hmmm, because we now work different days and only have 1 weekday off in common, however I responded enthusiastically.... but sure enough as that day approached she had far too much going on to see me.
But clearly it's just habit for her. So I forgive her because she is otherwise a great friend whose company I really enjoy. I do wish people wouldn't do this though.