Ohh... >_<

Our front left neighbours (we live in the back, they live next to our driveway) have five children ranging from age 0 to 10-ish (the youngest was born a few months ago). They're not really a nuisance during winter, but when the weather is nice, they play outside. Wait, they don't play, they SCREAM. Just that - they scream and occasionally they'll do something else while screaming. And eventually their mom will come out and scream at her kids to stop screaming.
Not only that, but a few years ago, one of their daughters decided she wanted a pony. What do the parents do? They buy half of their left neighbours' garden, build a fence around that half and a part of their own garden, and they put a horse in it. One that's too big for a little girl, she was only as tall as the horse's legs were. After a few weeks, the girl loses interest... and the parents dump all the horse shit on the dividing line with OUR property, providing us with year-round stink. Luckily that only lasted a few years, then they got rid of the horse.
Our left neighbours (they live next to our house itself) have just finished building their house, so they're relatively new. They have a labrador (I think), and every morning, they chase it onto OUR GARDEN to take a dump. While the dog's at it, it usually throws over the small kitchen-waste bin the law obliges us to have and tears apart the bags of waste in it, scattering coffee filters and rotting fruit peels and such in a 2m radius around the bin. Also, because there's a big dog in the garden, our own small dog does not dare to go outside alone anymore.

I told my mother to complain to them instead of swearing all over the place, but she doesn't want to "make the new neighbours feel unwelcomed". And she tells me she'll complain the next time the dog empties our bin, when it does she'll wait until it happens two more times and then she'll complain, ... It makes me want to force those people to build a fence around their garden >_<