Route53 API rate limits are per account and very low.
It sucks not being able to fix the production A record because somebody did a lot of changes on the staging zone.
I was also alarmed to see that dynamodb:DescribeStream is limited to 10 QPS per account, making low-latency stream consumers into noisy neighbors of each other. Then there's all the "open a support ticket" per-account limits on table provisioning and running EC2 instances…