On the storage front, even enterprise grade SSDs with hundreds of thousands of 4k read and write IOPs set up in over-provisioned arrays won't give you a great SLA unless you really lowball it and say the SLA is 99th percentile latency / IOPS is 1/2 benchmarked and the hardware has to sustain that latency/IOPS for 99.99% (after benchmarking out to figure out cache vs sustained performance)

That's just storage, now you need to add so many layers on top of it. Like @boulos said, it is then your fault, but your customers still see the issues.