Some comments are definitely a bit silly, like "See you later" from someone you know you're very unlikely to ever see again. I wouldn't normally get upset, however, at any well- intentioned comments as I think most are just meant to be friendly or helpful. I must admit things like " Cheer up - it may never happen" or "Nothing is that bad" can be thoughtless and hurtful ( although usually not meant to be). I would probably try to explain to the person that it is not a helpful comment and could actually cause people struggling with mental health issues or dealing with sad events a lot of distress. I would much rather have silly comments made to me than have no words exchanged with people who are working at checkouts, in a cafe, delivering parcels or just out walking their dog etc. My DH does laugh at me, though, as I seem to end up exchanging life stories with people I meet in a shopping queue or on the bus etc.