Annoying noises

Can anyone think of noises that really annoy you. I hate rustling crisp packets. It sounds so loud! 

  • Noises that I cannot identify.

    I have a big noise  problem at present.  Although the noise itself is small.

    I live in a block of flats, with flats above me, below me and along side. 

    I don't know my neighbours because I am an anti social recluse.

    At night I can hear a low buzzing sound, on and off, repeatedly all-night. It's not a washing machine, it's not a bathroom extractor fan. And it's not outside because I can't hear it when I open the window. I can't see any air-conditioning boxes on my building.

    The best way I can describe it, is that it's like a mechanical or electrical noise such as being near a fridge switching on and off.

    It's only at night, not during the daytime.  My sister has suggested it could be triggered by darkness. Such as artificial light which is not needed during daylight hours.

    The problem started in April, soon after we went into lockdown and the letting agency suspended it's routine inspection of the flats.

    So is the noise related to something illegal?  I don't know, but it's driving me nuts.