The Laboratory Manager is a unique position in the lab and a quite stressful one. Lets face it, you take shit from three sides: THE MAN (the PI), the front lines (folks working at the bench in the lab), and THE BUREAUCRACY (accountants, safety folks, HR, etc). So while they are balancing satisfying this week's whim that the PI has a scientific boner for, they are also calling to get the -80 repaired, making sure everyone has their radiation safety training certificates documented, getting PO's to order all the shit you need, and whats that there is an internal audit going on? Hopefully the PI treats the Lab Manager like gold because they are the constant in the lab. Grad students, postdocs, and techs, they come and go, but this person stays with the PI throughout most of their career if not all depending on circumstances. So from a PI's perspective THE MAN wants to keep the Lab Manager happy.
So why should you guys on the front line keep the lab manager happy? Um, maybe because they order all of your stuff, which entails going through mounds of paperwork and red tape. They make sure you have the basic essentials in the lab and all the stuff in the lab is working. I have had the misfortune to spend six months working for a horrible lab manager who I considered to be nothing more than a piece of shit. Orders were not regularly placed, in fact one month it took three and half weeks to get her to place an order. So its hard to do work when you run out of pipet tips and lets face it, THE MAN doesn't care if you are out of tips, he wants that data right fucking now. And all this person cared to do was play on their new iPhone all day.
Luckily I have moved on from that lab and lab manager (both of which essentially crashed and burned since I left). I now have the good fortune of having an amazing lab manager, she will bend over backward to make sure everyone in the lab is happy and everything is running smooth. In return, I will fucking rape and pillage like Attila the Hun to keep her happy. I routinely intercept vendors so they don't bother her (although that didn't turn out so well), take them to lunch and pitch in any time a new piece of equipment needs to be set up or calibrated, in essence just be a good fucking labmate. These people work hard to make you happy and hopefully successful, watch out for them and they'll watch out for you.
Now as far as the third front, THE ADMIN, they just don't give a fuck about the Lab Manager. Man, sometimes you just can't go R-E-S-P-E-C-T!