It's surprising in a positive way that the cheap little kit antennas of the RTL-SDR allow me to receive some ADS-B data from within my apartment with no clear view to the sky or horizon in any direction :)
Also receiving temperature and humidity sensor data from cars and weather stations is crazy. No need for your own weather station :D
I definitely feel the appeal of this particular nerd rabbit hole. Caught myself reading about DIY antenna builds already :D