3 strings wanted a beer from the bar

The first piece of string walks into the bar and asks the bartender for a beer. The bartender surprisingly looks at him and says:
"Aren't you a piece of string?".

The 1st piece of string replies, "Why yes I am sir. I just need a nice cold beer."

"I'm afraid we don't serve to strings," the bartender replied. The 1st piece of string strolls out. The 2nd piece of string sees this and gets discouraged, but decides he will still give it a shot. The 2nd piece decides to go into the bar anyway and proceeds to ask the bartender for a beer. The bartender, now even more confused, asks the 2nd string the same question:

"Aren't you a piece of string? I'm afraid I cannot serve a piece of string," the bartender informs the 2nd string with a regretful reply. The 2nd piece of string expected this and strolls out of the bar, beerless and sad. The 3rd piece of string has seen both his friends rejected, but is DYING for a beer. He had a long day and gets a light bulb idea. String 3 decides he's going to throw a little disguise. He decides to tie himself in a knot, ruffle up the ends of his knot a bit, and get the string look out as much as possible. After being satisfied with his disguise he puffs out his chest and walks into the bar. Instantly, the bartender sees right through his disguise. The 3rd string walks up to the bar anyway:

"I'll take an ice cold beer please," string 3 claims confidently.

"Aren't you just a string, like both of your other friends?," quickly replies the bartender.

"No sir, I'm a frayed knot."