aws s3 --include, --exclude not working

It turns out that the order of the --exclude and --include flags passed to aws s3 sync and aws s3 cp matters, so

aws s3 sync 's3://my-bucket' . --include '*.png' --exclude '*'

won't download anything but

aws s3 sync 's3://my-bucket' . --exclude '*' --include '*.png'

will download all PNGs in the "root" of the bucket.