I will try to keep this as short and to the point as possible, please bare with me!
A few years ago, before DC I worked as a nanny. I mostly worked as a mothers help doing after school hours when the mother was also there.
It was my first job after a breakdown, I was young (18 I think) and I had little experience of working. There was no contract so Im pretty sure it wasn't legal (I had no knowledge of a contract being required) I worked there for a year.
The mother was an absolute nightmare. Everything I did was wrong. She'd say nothing to my face then send emails when I got home asking me to do things differently next time. She even wanted me to chop garlic her way ffs! She also shouted at me a few times, when the kids were playing up and she was stressed.
I became miserable and felt like I must be bad at my job. I had low self esteem as it was but this made it so much lower.
Things concluded when I found out I was pregnant. I knew they would want to find someone else and to be honest was glad to have an excuse to get away from the job. I let them know I wanted to work as long as I possibly could (I knew I would need the money) but understood they would want to find somebody knew and I was happy to help them search. This was all spoken about and we seemed to agree. I went home for the weekend and received an email on the Monday saying they think it would be best if we terminated the job now, and asking for the wages they had paid me back!! They also said I 'owed' them two nights babysitting which is something that had never been agreed on and I still don't know where that came from.
I let them know I would be keeping my wages and I wouldn't be babysitting for them. She went on to send me loads of emails saying I can't do that, how I shouldn't run away from my problems and how would I ever be a good parent with my attitude. She also asked if she could email my mother to discuss things with her instead 
I ended up having to ignore her, posted her door keys back and tried to forget the whole thing although it left me really upset.
Fast forward to now my DS is 2 and we now live in an area not far from theirs. Today I saw her for the first time since working for her at a playgroup in between our areas. I wanted to run away/cry but stuck it out and ignored her. I have friends at this playgroup and she didnt seem to know anybody and I suppose for that reason she decided to come up to me and say hey how have you been etc as if nothing happened. I just looked at her like she had grown two heads and then carried on what I was doing. Childish maybe but I really don't want to play nicey nicey with someone who made me feel so low at a time when I was very vulnerable.
AIBU to think she is bonkers and mean and not want to pretend like nothing happened?
Thanks if you got this far 