What's the first command you run upon jumping on a wayward Linux box to try to troubleshoot something? For me, it's almost always "w". Unless I have data pointing me in some other direction before landing on the system, I like to see that as a sort of "first snapshot" of what the box is up to before I go off and possibly do other things.
Why bother? Well, over the years, I've discovered a number of bizarre things just from the odd little bits of data which will be returned in that command's output.