I need helping understanding this story, and one of my questions

go to a bar, itll make more sense there

to quickly take on the persona of someone in that environment, ie. adapt yourself to it

Well, I think it's just a true observation about humans. We tend to fall in line, adopt speech patterns, lingo and mannerisms of our surroundings, our job descriptions, our perceived identity. This is especially true for young impressionable people ("boys") looking for a greater sense of belonging. In adopting the parlance we give up a little of our own identity, it seemingly turns us into someone else. Outsiders can see, this is a lie. But it suits us. The act gives us confidence. "I'm not a school boy anymore - I'm now a hardned sailor, don't you see?" We pile up these heaps of lingo to ridiculous heights, just to boost our self-importance. The less "commoners" can understand us, the better and the more superior we feel. This is how young insecure people build identity.

It takes a lifetime of experience and insight to tone it down again, to realize that the most impressive feat is to blend in, to have extensive niche knowledge and overwhealming power, but talk so everyone still understands you and to still seem innocent and approachable.

That's what the sentence means to me, anyway :-)