Namaste
As we’ve said time and again, sharing thin walls means having to compromise sometimes. Having said that, we’re not sure this counts as a compromise. The OP received a message from their neighbor asking them what exactly they were listening to and when they told him it was guided meditation, he added that it made him want to “murder someone.”
Seeing this as the perfect opportunity to bring him on board, the OP told him to listen along and take deep breaths. This only made him angrier but it looks like the OP won this round. The “Namaste” in the end was an unexpected and hilarious cherry on the cake.