Or in the case of me a year ago, your ISP is screwing you over with their overloaded network that was damaged, but did not inform anybody and denied it was actually having issues until I complained to them every single day for a whole month. 6 months later, they finally fixed the network and all my ping fluctuation and spikes went away. Reason ISP didnt care as much is because only picky games requiring minimal fluctuation would be affected, which to them, is an incredibly small market, compared to businesses and residents who just want the internet to work so they can browse the web and stream videos, where fluctuation has basically no effect.