“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” A popular joke involves a bear who walks into a bar and says, “I’ll have a beer…....and pretzels.” The bartender says, “Why the big pause?” The bear responds, “I don’t know, I was just born with them.”
 
The joke has been cited in print since at least 1998.
 
     
rec.humor
This guy walks into a bar…
Mark Ballard
2/10/98
A bear walks into a bar and says
” I’d like a beer and ............................................................................ a packet of peanuts”
The barman says ” Why the big pause?”
 
Google Groups: rec.humor
The FCC can end all newsgroups
Chris Jones
11/14/98
(...)
A bear walks into a bar and says “I’ll have a pint of beer…....
........ ........  ....... ...... ......and a packet of crisps.”. The barman says “Why the big pause?”.
 
(paws, geddit?)
 
Google Groups: rec.motorcycles.harley
OT Joke for Greasy….
Len
12/17/99
Maybe it’s because it’s Friday, I don’t know but this hit me as hilarious.
 
A Polar bear walks into a bar and says to the bartender, “I’ll have a gin….......
.
.
.
.
.
.
.
.
.............................and tonic”.
 
Bartender says, “What’s with the big pause?”
 
Bear says, “I dunno…I’ve always had them.”
 
Straight Dope Message Board
Good Joke
H8_2_W8
07-25-2000, 03:57 PM
A Grizzly Bear walks into a bar. The bartender asks “What’ll you have?”
 
“Ummmm,uhhhh,ummmm,uhhhhhhhhhh ... a beer and a shot,” the bear finally says.
 
“Why the long pause?” the bartender asks.
 
The bear holds up his forearms and says, “I dunno, I was just born this way.”
     
Google Books
A Prairie Home Companion Pretty Good Joke Book
BY Brian Becker
Minneapolis, MN: HighBridge
2003
Pg. 119:
A bear walks into a bar and says, “I’d like a beer and…..............a packet of peanuts. The barman says, “Why the big pause?”
 
Google Books
A Guy Walks Into A Bar…:
501 Bar Jokes, Stories, Anecdotes, Quips, Quotes, Riddle and Wisecracks
By Michael Lewis
New York, NY: Workman Publishing Company
2005
Pg. 95:
A Polar bear walks into a bar and says to the bartender, I ll have a gin…....and tonic.
 
What’s with the big pause? the bartender asks.
 
I don t know, the bear says. My dad had them, too.
 
Google Books
Man Walks into a Bar:
Over 6,000 of the Most Hilarious Jokes, Funniest Insults and Gut-Busting One-Liners
By Stephen Arnott and Mike Haskins
Berkeley, CA: Ulysses Press
2007
Pg. 114:
A bear walks into a bar and says to the bartender, “I’ll have a whisky and ......... soda.” The bartender says, “Why the big pause?” “Dunno,” says the bear. “I’ve always had them.”
 
Google Books
The Mammoth Book of Really Silly Jokes
Edited by Geoff Tibballs
London: Constable & Robinson Ltd.
2011
Pg. 16:
A bear walks into a bar. He goes up to the bartender and says, “Please could I have a…” thinks for a moment and continues, “beer.” 
The bartender replies, “Why the big pause?”