The worst for me was with the Nexus 6P, the last phone before they rebranded to Pixel. There was a known issue with the battery, where it would die when the phone said it was at like 50%. I jumped through all their troubleshooting hoops when it was obviously a hardware issue. They eventually agreed to send out a replacement and I was assured it wouldn’t have the issue. Lo and behold, it did the exact same thing as soon as I got it. I went through all the trouble shooting again and they sent ANOTHER replacement that still had the issue. I was so fed up and just kept requesting to talk to someone higher up and they eventually just sent me a Pixel 1 to shut me up.