<human>: My mother and sister recently came to visit my university for an open day. I'm currently on a placement year for my degree, but made arrangements to meet them for lunch. I offered to take them on a tour of the campus, but my sister wanted to go around by herself - which I was happy to agree with.

However, once I met up with them my sister threw a tantrum (and I mean screaming/crying) because I was ruining her day, even though we had kept to the original plan. My sister wanted to stay longer at the university (fine) but I couldn't be there, demanding that I travelled an hour home and then an hour back when she was 'ready'. When I refused, she then ran off and basically got lost in the city, refusing to answer her phone. This meant that me and my mother had to abandon our plans and try and find her.

This is not unusual behaviour and tbh I'm fed up of it. I told my mother that if this was her reaction, that I would leave and let my sister calm down. My mother's response to this was that we were ruining her day out; and she basically blamed me for my poor relationship with my sister because I'm older and should know better. I have bent over backwards to accommodate my sister and I'm sick to death of being blamed for her behaviour because I'm a convenient target who ends up apologising.

My sister eventually returned, but wouldn't allow us to do anything as a family after this point. I'd not seen my mother for 2 months prior to this incident, and am unlikely to see her again until September. I've told my mother that if my sister can't apologise or change her behaviour then I no longer want to be in contact with her until she can, basically, grow up.

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<bot>: My sister acts unbelievable childishly to get her own way and control situations, particularly to limit my contact with my mother. Going 'no contact' with my sister will deteriorate my relationship with my mother.