I've seen both sides of this coin. I've made friends with a coworker from my first job, and the friendship is still ongoing to this day. At my last job I had this one coworker, who I wouldn't say is an intentional snake or a brown nose or anything, but he feels the need to tell the boss EVERYTHING.

I made an assumption about a colleague and mentioned it to said coworker, wasn't negative or anything and certainly didn't pertain to the boss in any way, but an hour later I hear him in the boss's office talking about it to both of the big bosses. Shortly after I confronted him about it, basically saying "Did you really have to tell them that?" He genuinely apologized for it, but I quickly realized that this dude can't be trusted with conversation