I had a coworker who was frustrated by a newbie who needed a lot of help in the field. "She can't even turn on a generator!"
I have to admit that I became an equipment rental company's "dart target of the week" once myself, and it was a generator that pushed them over the top.
I'd already called several times that week about other non-functional equipment that didn't respond well to phone coaching, so I'd already exhausted the rental company's patience.
This was when the new generation of smaller, enclosed generators became available (i.e. not the giant rattle-y metal ones). The generator kept shutting off, and nothing we did could keep it running. Notice the "we". I had several people with me in the field, and one person had some background in keeping engines running. I kept calling the rental folks, they would suggest different things, it would re-start fine, and then it would die 5-10 minutes later. The same thing happened with the replacement generator they sent out. You can see why they were starting to get irritated...
Experienced field folks may be able to guess what was wrong...there's an itty-bitty switch on the gas cap itself that needs to be in a particular position. If it's not open, air can't get in and the generator dies.
The problem is that basic field equipment like generators don't necessarily come with instruction manuals. Sure, I can operate one now (assuming I can yank the cord properly), but I certainly remember how it feels to be mystified by something that's supposedly basic.