To blank my ex-manager

No one likes being forced out but it seems to have worked out well for you. You like your new manager and I assume you’re enjoying and flourishing in your new position. I’m not saying you owe her any gratitude but carrying resentment only makes you feel bad, she’s still spoiling your day to that extent.

You do need to reply when she says good morning. Being a rather petty person, I would respond cheerfully but somewhat absentmindedly, as though I’d heard her but had much better things on my mind and I wouldn’t break my stride because I had much better places to be. It’s really dismissive without being at all rude.

Just nod.
You will store up trouble for yourself in the future if you blank her.

Feel victorious every time you see her and give her a little victory smile and a slightly pointed stare. You can’t be criticised for this. She’ll feel uncomfortable but won’t be able to put her finger on why.

No it's not. You can keep a professional stance but still keep the problem at arms length.

Smile, nod, never be heard to say a bad word about her, but never stop for a chat - always be running somewhere when you see her.

I had similar. Right nasty bitch. I moved internally and was managing a new team. She reached out needing help from my team. Yeah, over my dead body. Professional response was unfortunately we have a number of key deadlines at the moment and I'm not able to spare anyone to assist.

Be the better person. Polite hello and move on.

Blanking someone in a work context (actually in most contexts) is unprofessional and would make you come over as petty and immature. Which, as an outsider, would make me wonder whether your ex manager had a point in getting you to move on.

Brisk hello and keep on walking

You're not doing this for her sake. You're doing this for you to demonstrate to colleagues / employer that you know how to behave in the workplace, even if your ex manager doesn't

Approach with a giant smile on your face. When she speaks, drop the smile and give either a straight faced nod in her direction or a flat “hi” and keep moving. Once past her plaster the smile on again. Anyone else watching will see the difference in your attitude, but it doesn’t give her any ammunition for HR.

Erm, she's at work so actually, bottling it up is by far the best plan if she wants to keep her job.

Protecting her mental health by ignoring her ex manager whilst on work premises is a shockingly bad idea.

It is always best to remain professional and remember you are at work, not the school playground.

At the end of the day it comes down to this. What will protect your mental health? If you think ignoring her protects it, great.
If spelling it out makes you feel better, go for it.
But the fact is it's not going to help bottling things up

Telling colleagues how delighted you are to have moved department with NO specifics can tell its own story too.

Maybe, show how happy you are to be away from her, flounce through looking your happiest.

The barest, coldest hello, no looking directly at her.
I hope you have kept careful notes of what occurred.
You never know when they might be useful.

This type know well they are pricks, and that you can't stand them.
They like to continue to bully by forcing contact.

I had one like that.
I dead eyed him when contact was forced.

I layed very low in the grass for two years and when the chance came and I accidentally came across some really damaging professional information about them, I royally fxxked them over.

Deeply satisfying.

Also another boss that was deeply unpleasant that after I moved department had a serious Grievance made against him.
I heard about it and approached HR with a signed statement of what I witnessed, had had said to me.
He was put on gardening leave immediately after I gave my statement and HR realised that they were likely to have several other statements coming their way as staff were openly talking about it.
He never returned.

You never know when your moment might come.
We also ensured that both reputations followed them to their new positions when we learned where they had gone.

Don't look her properly in the eye. Just say "hi" and do a cursory fake smile, so you're not rude, but make it obvious that you have no interest whatsoever in conversing with her.

I would recommend being polite and professional, it is work not social. You don’t have to like colleagues of any level but you could get into trouble for being rude.

Even if the don’t, if you behave impeccably, you have the inner satisfaction of knowing you occupy the moral high ground.

Be the bigger person. You’ll make her feel much worse if you are always charming and friendly when she knows she doesn’t deserve it,

Absolutely don’t blank her. You need to be professional and acknowledge her but nothing more.

Feel resentful away but how you behave should not be powered by her but by you and your interests instead.

Control your behaviour because you are doing that for you, never control your feelings.

She still works at the organisation so look to the bigger picture. It would look bad for you if you were caught blanking her. Just say a very cold hello.

I’m nearly certain this was where voodoo doll’s come from.