How do reverse-engineers feel comfortable with not knowing the 'big picture'?

One of the biggest barriers in my journey of learning reverse-engineering seems to be the fact that I feel rather uncomfortable being confused about the ‘big picture’ of what I am reversing and not knowing the exact design of a program or every line of a certain function etc. I am just very uncomfortable with a large portion of it being unknown to me.

For example, at the moment my job is to reverse-engineer one single data flow from kernel-land to drivers. But I am getting side-tracked into trying to make sense of some of how some of the processes I’m looking at interact IPC-wise, even if it’s irrelevant to the data flow I’m meant to be analysing.

What do professional reverse-engineers think I can take into consideration or do methodically that will help me get more comfortable with being uncomfortable, as I am never going to understand every bit of how certain functions, programs, systems work when analysing them.