AIBU to be annoyed neighbour put spikes on the fence?

Poor mental health or dementia are certainly possibilities but I doubt the OP will be back @WhereYouLeftIt, having committed the three cardinal MN sins, ie owning a free range cat, having a trampoline and admitting that her child throws balls in the garden.
My mother's elderly neighbour became very distant and unfriendly following the loss of her adult son, and complained about the slightest incursion over the boundary, so it may be grief, you never know what is going on in someone's life.

Which type @SunnyLuny?

what a great idea , my neighbours cats are the bane of my life , I got a sensor deterrent but but really helping , off to look for spikes now

Off subject a bit, but I put spikes on our fences to attempt to keep our cats in. A day later I found one of them patrolling the perimeter of the garden along the top of the spiked fence, so your cat may do the same……..we ended up having to put proper cat proof fencing in to keep the little darlings safe.

Exactly. The whole roaming cat thing is obsolete in a modern world.

Add in the fucking trampoline placed right near her border and I totally get why she washed her hands of OP.

Can I suggest an alternative to her having an issue with your cat?

A few years ago during the lockdowns, someone I had previously been friends with started to behave as your neighbour now does - looking down so she wouldn't look me/anyone in the eye, walking past you in the street. I put it down to depression/nervousness about life in lockdown.

It was actually dementia; she was young, mid-fifties, so I hadn't even considered that as a possibility. You say this lady lives alone, so there's nobody there to pick up on behaviour changes. Does she have many visitors, family coming round?

OP I would just cat proof your garden and leave her to it.

I certainly wouldn’t be sending her a card or trying to make amends!

She’s a grown woman for Christ sake

You can do that yourself. We got the supplies from e bay.

Yep...think I agree with that. She can put the spikes up if she wants. I don't think it's something you should take issue with.

You changed things by getting a cat which more than likely she doesnt want in her garden. You have already stated you wouldnt have an issue with the spikes if she had asked. So really the only issue is you.

The spikes will help her keep your cat out of her garden. Your car may learn not to go in. Its not the law that neighbours have to speak to each other so whats the issue?

My mil doesn't like cats because they scare away the birds. It might be that. Maybe she wants to feed and watch the birds...and she can't because the birds all know there's a cat to avoid.

If you have a litter tray which he uses and you find a normal amount of cat shit in it then I think it's very unlikely he's crapping all over the neighbour's garden as well. This is just an assumption that PP are making based on their own experiences and dislike of cats.

I have the same, a cat who goes out but prefers his litter tray and I know how much he craps because he has had to be kept indoors for medical reasons before. I know he's doing it in his tray because I'm tidying it up! He doesn't have a magical ability to produce extra shit when he's allowed out compared to when he's confined indoors. OP, you probably know if this also applies to your cat.

It could well be a different cat or yours is doing something else she doesn't like, like nibbling her plants or stalking birds. I would let her know that she had my full support to spray the cat with a water gun or turn the hose on him if he's making a nuisance of himself. But of course she's being silly to just start blanking you! That's not a sensible way to deal with any issue.

I like all the responses haughtily insisting that OP should cat-proof her garden and in fact, should've cat-proofed her garden before she got the cat...as if that's a thing that cat owners in the UK commonly do and is viewed as a social obligation.
It's not...and it's not.
Some of you may think it should be...but cats in the UK generally roam free as standard. How many cat-proofed gardens do you know of? I can think of two. I know a lot more households with cats than two.

You should have cat proofed your garden before you got the cat OP.

Your pet is probably shitting in her garden and if it is, it is your responsibility to deal with it. Neighbours should not suffer the consequences of your decisions.

I don’t understand stand why you haven’t just gone round and knocked on her door and asked her. All this guessing why she’s upset and writing notes. Just talk to her.

Well I think ideally people wouldn’t choose to own pets which are 100% likely to cause a nuisance to other people who haven’t chosen to own a pet. That means unless you live a considerable distance from neighbours, what I reasonably expect cat owners to do is keep their cats on their own property instead of shrugging their shoulders and allowing them to use the neighbour’s gardens as a litter tray and destroy wildlife.

Consult your neighbours before you get a cat? 🤪

It’s horrible having cat shit in your garden. I’ve trodden in it several times. I’ve just cleared some more up! I’ve bleached the pebbled area that next door’s cat has adopted as his litter tray. I’m not surprised your neighbour is pissed off with you.

Quite. I bet she's well and truly over it.

She’s quiet and keeps to herself; how is that “difficult “??

If only others would do the same.

Shitting cat, noisy kid, trampoline by her border, balls coming over the fence. Gee, I can’t imagine why she thinks you’re undesirable as neighbours.

Are cats the new XL bullies? 😅

Why would she need to tell you she has an issue with your cat? Are you under the impression that some people like cat shit in their gardens and others don’t? You can just assume that no one wants your cat in their garden and they have an issue with it. It’s more likely if anyone doesn’t have an issue they’ll tell you.

She sounds crazy, I wouldn’t worry about it.