How awful was this parenting failure? Be honest

Toddlers have moments like this all day!

This is bang on.
Most people will not remember anything much from their toddler years. If it's a pattern of disappointment then maybe but a one off (which then didnt even happen) will not be etched permanently on their psyche

None of us are perfect parents. Your toddler had a good day.

I think you’re overthinking this. Your toddler will not remover this tomorrow. They probably forgot after 15 minutes of being at the park.
We all have disappointments in life and we can’t be shielded from all of them. We have to learn how to deal with them. It’s called growing up. Teach your toddler (as they get older) how to cope or they’ll have no resilience.
Keep all of these thoughts to yourself. You’re being hypersensitive

The kid will get over such a silly encounter. Don't make it a thing.

Well, my sister actually did drag her kids away from a promised outing and sleepover on the grounds that ‘she didn’t feel comfortable’ after what had been until that point a disagreement between the adults. None of the cousins ever saw each other again!

That was a parenting fail. What you did wasn’t ideal but you salvaged it, you both got control of yourselves and put the children first, as adults should. It will be ok. You salvaged it.

Op it wasn’t ruined though your being too hard on yourself you needed to protect yourself then your sister backed off so nothing to be concerned about. Even if you had left your dc would have got over it.

They won’t remember. You learnt a lesson, cut yourself some (a lot) of slack.

Op your toddler won’t even remember 🥰

It is a trivial matter. It's not your job to protect your child from all disappointment forever.

I hear you, but please don’t beat yourself up about it, you’ll remember but your toddler won’t. We all get things wrong sometimes, it all turned out good in the end 😀

Toddlers live in the moment.
Quickly forgotten. Move on and don't say things like that in front of her if it will worry you.
Thousands of toddlers had much worse days today and she had fun.

You quickly turned the situation around and toddler had a happy day. They don't bear grudges at that age so I would focus more on what's going on with sis/fam

Yes she does

Your toddler is fine, I can almost guarantee they will not think anymore about the moment they nearly didn't go to the park and will only remember the fun they had. In their mind, it was a good day.

But you caused that moment. Just remember that even young children can take in what we say and our emotions. Why do you think parents spell things out and use discreet facial gestures?

Forget the incident now because your toddler definitely will have, but think before you speak next time and remember you have an audience.

We all do silly things and we all make mistakes. Just forget it.

Toddler had a good day. No harm done. Forget about it (as the toddler will have done).

As previous poster has said, she won't remember it, she went on to have a lovely day. You are suffering from mum guilt, hopefully it will fade over time

You stayed and your kid had a good day it’s your mind overthinking it now try to distract yourself your kid won’t remember it he had a good time .

That's nothing. My mother once cancelled my birthday party because she had an argument with my older sister. I still remember it 40 years later. 😩

I understand you feel bad that your toddler thought for a moment that the much anticipated day was not going to happen. But, honestly kids are resilient and live in the moment ,i hope you all had a wonderful day because thats the cure for these momentary feelings of disappointment.
As for your sister ,she seems to have been insensitive (but its hard to say not knowing her or the issue) . As for you saying you'd go home because your sister wouldn't drop it when you asked her to, again, without knowing the issue its difficult to say wether you have an impulse control issue or were fully justified.
I really hope you all had a lovely day.

We can't protect children completely from the fact we are - like them - human and sometimes irrational!

Don't beat yourself up, you feel bad, move on now.

No human on earth grew up never seeing their parent have a bad moment or make a stupid unncessary threat.

Nobody is perfect and your toddler will not remember as the day we ahead as planned. We all learn from our mistakes. Sorry your sister upset you, hopefully she has learn't something from it. Be kind to yourself, you are a good mum.

Your toddler is unlikely to remember but just learn from this. It is hard to say who was at fault without not knowing the issue. I would contact your sister and tell her that the next time you ask to change the topic or wait till later to talk about it that she needs to respect that and that through an open car window in a car park is not the place for most conversations.

To be honest you sound like someone who reacts very strongly to situations. The "I'm going home" reaction to this feeling terrible and guilty over a 30 second emotional experience that your toddler will have forgotten by now, both seem quite over the top without any additional context.

Do you often find you react really strongly to situations? Is there something going on in your life to make this more so?