Today 10 years ago I went to Poland to buy a Phone with pre installed #Firefox OS on. The Phone was a Alcatel One, so very shitty. Two years later I installed Firefox OS on my Nexus 5 instead.
It was a very good concept, but sadly rolled out on too shitty hardware so it never caught on.
My Nexus 6 was the worst phone I've ever had. It aged like milk. It was so bad I jumped off Google phones and never went back. Getting the OnePlus 3T was like breathing fresh air again.
Edit: had the Nexus S and Nexus 4 before the 6, loved those phones... So jumping off Nexus was no small matter.