This whole problem started when I put in my above ground pool.
The neighbor who used to be friendly (he even snowblowed my driveway once, without my asking) explained that his inground pool was a "focal point" of his yard, and that my pool would cause a drop in his homes "curbside appeal".

He called the township because I was cutting a 10' wide path in the weeds of some township-owned open space behind my yard. This was so my 11 & 8 year-old girls could walk out back to see the neighbors horses.