randomly venting to people

i honestly hate it when someone just starts venting out of nowhere. like, we'll be having a good conversation and then they just decide to bring up how their only mother figure would be their sister?? like damn, sorry about that but what am i supposed to do? be your mother?

and i get that its good to listen to them, and i do listen. maybe even give some advice if they want it. but when they just start doing it out of nowhere it really bothers me. and then when i try to vent they change the topic. like, hello? i have problems too. i know, its absolutely shocking. 

venting also makes me super uncomfortable. especially when the problem doesnt have anything to do with me and then im just stuck there listening to how much they hate their family. 

anyways, if you plan on venting to me, just give a warning first atleast