This question was inspired by my hatred of Temporal Anti-Aliasing which, in many games nowadays, is poorly used as a performance bandaid. On lower resolutions it will smudge and blur the image and certain bad cases of TAA will cause visible ghosting.
Yet in spite of all this, certain games won't let you turn it off or have hair/fur/foliage look like dogshit without it so sometimes I still use it.
My vote goes to Google, to whom I am tightly married. It's ecosystem and interconnectivity between apps as well as devices is unbeatable. It's super reliant.
It's the one entity that can wreck my online and offline presence. I mean, I use android and Google to login everywhere. If Mr. Google so decrees, my phone could wipe and google account be gone tomorrow. Same applies to Apple and Microsoft, but I don't use their systems as much. The poison I picked is Google and I hate it.