I'd argue that timezone is just part of the problem. If you're responsible for a high oncall load, you are subjected to a steady, unpredictable stream of interr

I'd argue that timezone is just part of the problem. If you're responsible for a high oncall load, you are subjected to a steady, unpredictable stream of interrupts requiring you to act to minimize downtime or degradation. Obviously it's worse if you get these at night, but it's still bad during the day. I think the anti-pattern is having one team responsible for another's burden. You want teams to both be responsible for fixing their own systems when they break, AND be empowered to build/fix their broken systems to minimize oncall incidents.