Background: my neighbours has a holiday house across the road from us, at weekends in the summer they often throw loud and large parties that go on to 1-2am in the morning, and she has an extremely loud voice that I can hear from my house. This is over a period of about 15 years.
Said neighbours have a DD about my DD's age that use to play together when they were young, so I would sort of friendly to them, and sometimes I would babysit their DD when they threw their parties
but bit my tongue for the sake of their friendship. Their friendship fizzled out in the early 2010s about when they both started secondary school as their DD came out to the house less.
DD and I have barely talked to them since then, and have since rang noise control a few times since the friendship ended if their music if its still going after midnight. Maybe its because I have got older and my tolerance of their music keeps decreasing as the years have gone on.
Just bumped into them in the street and they told me that they are hosting their DD's 21st on NYE (she is born on the 1st), they said we (i.e DD and I) can either complain or join us
I thought that was fucking cheeky, she then said their parties are no longer as loud because they have got older
Which I dispute, but its beside the point as its their DD's 21st.
Wtaf, so she knows that they been inconsiderate to myself and other neighbours for the past 15 years, yet she still does not care 
Fwiw I will not be calling noise control because it is her DD's 21st and NYE. But I am still fucking furious, like hell we are going to go her party given its been the best part of a decade since we have spoken to both them and the DD.