Being "that guy" does not actually come naturally. It takes time and practice, and while one can aspire to be "that guy," it can't happen without first becoming a "douche" an "asshole" and the stage just before "that guy", a "dick."
When trying to be "that guy" it's best to start small. Follow these simple suggestions and you'll be on your way.
Grow a mustache. Especially if you can't grow a mustache, and there's only a few errant non-head-hair matching hairs hanging out over your lip.
To be "that guy," outdated jokes and vernacular are critical. i.e. 1992 called, they want their flannel back. (uh, incidentally … 1992 called, they want their joke back.)
One word: NASCAR
Read one, and only one book in your entire life: The DaVinci Code
Master these four easy steps and you'll easily be deemed a douche.
The next steps require a more active role in your "That Guyness" growth.
Answer your cell phone in a movie theater. While the movie is playing. And have a conversation. When people give you dirty looks, look right back at them with an "excuse me, I'm having a conversation here look."
This behavior automatically makes you an asshole. Congratulations!
Getting in people's way and staying there makes you a dick, and here are a couple sure fire ways to be one.
When boarding an airplane, particularly a super full flight, make sure you are sitting towards the front, and that you board first. Aisle 10 is good. When you get to aisle 10, put your luggage down in the aisle and spend a good 3-4 minutes getting yourself situated while the people behind you cannot get by. Sit in the aisle seat, even if you are assigned the window and then wait for the person who has the aisle assigned to show up and ask you to move.
Bonus points if right before the doors close you make a call on your cell phone, ignore both requests to turn it off (the flight attendant and the Captain,) and have to have the flight attendant tap you on the shoulder before you will comply.
Here's another winner, when ordering to go food, be sure to stand in front of the cash registers until you get your food so that no one else can order. This technique can also be applied to ordering food by blocking the cash register while reading the menu and not allowing others to get in front of you even if they already know what they are having.
Once you have mastered all three stages, you will be "That Guy."
I am often asked, is there no fast track to being that guy? There is one. But it's dangerous, so I urge you to use extreme caution when deploying this method. It can only occur in Vegas.
Drink Jager shots at the Blackjack table, even though you are 39 years old and down a thousand dollars (side note: If you don't want to be "that guy" you stop drinking Jager when you are 22.)
Jager drinkers fast forward through douche and instantly become assholes, if they vomit as a result of drinking too much Jager and the vomit hits another person they get a free pass to "dick." If, the next day, with a hangover that would make Nicolas Cage in Leaving Las Vegas look like he was carrying around a 10-years-sober chip, they drink even one shot of Jager they instantly become "that guy." Thus, in 24-hours in Vegas, one could potentially become "that guy."
Bonus points if you use the "What happens here, stays here" line in someplace not Vegas. i.e. What Happens in New Foundland, Stays in New Foundland.
Being inconsiderate, obnoxious and kind of a douche takes work. But if you follow the guidelines outlined above, you too could be "That Guy."
Uh, good luck?