It’s an important question any time you’re trying to improve something.
In software, developers very often use the phrase “it works on my machine” and this can be maddening to a user experiencing a bug. Except for the lazy developer, what the phrase really means is “there’s something different between my environment and yours, that’s responsible for this anomalous behaviour”. Working out the difference is a crucial part of trouble-shooting.
With people, when seemingly opposite stances are taken we also need to look for the differences in environment (real and perceived) to break a deadlock. If we understand why someone else interprets the same facts differently, we can move nearer to common ground – and/or change the (real or perceived) environment to mutual benefit.
It’s not just the difference between where we are and where we want to go – the difference in how other people see where they are and the destination is hugely important, too.