I'm not saying you can't make friends with someone you work with, but it's not the case 99 percent of the time, especially if there is any way you fucking up could advance them, or even any knowledge you leak to them could hurt you or advance them.

I'm 44 and have run a mid-sized company, worked in all sorts of corporate settings, and the only people I've ever stayed friends with after working with them were people I worked with in the bar business(generally no reason to hate on someone in that line of work if they are good, because hiring someone bad to replace them ends up making YOUR life a living hell).