Are people shouting in your datacentre? They should be...
Management of physical infrastracture is rare these days after cloud providers have abstracted the layer away from developers. However the same problems that plagued server operators of the past can still manifest themselves today.
It is important as a cloud native application developer to be able to identify whether the problem is with your code, or with the datacenter's service delivery. Watch linux performance expert Brendan Gregg's demonstration of physical disturbances in your datacenter that can directly affect application performance. Knowing how to investigate application performance will set you appart from the pack.
If you'd like to be mentored in hardcore application performance analysis, set up a time and we can go through your code together.