Vice President Joe Biden, lover of both Vets and 'vettes, says he's considering another run at the White House in 2016. And in typical Biden fashion, he told CNN Thursday that there wasn't really a good reason why he should sit out the race.

"There may be reasons I don't run," he said, "but there's no obvious reason for me why I think I should not run."

Certainly, Biden has some selling points in a Democratic primary. He's raised his profile and bolstered his resume as VP, he publicly embraced marriage equality before President Obama, and he is, at bottom, an affable dude.

Seriously, look at him kicking back with these bikers:

(AP Photo/Carolyn Kaster, File)

Hypothetical dialogue:

Biker guy on left: "Do we have to kill him now?"

Biker guy on right: "I…I don't know. He's so danged cool."

It's the old, "Which candidate would you rather have a beer with?" question, and the answer is: this guy:

(AP Photo/Carolyn Kaster, File)

Still, there are a few "obvious" reasons Biden may want to reconsider running.

He's unpopular
While Biden is well-known, he's not well-liked. A recent PPP survey found that almost half of voters (49 percent) had an unfavorable impression of him, while only 35 percent said the opposite. That kind of ingrained opinion is tough to change when there aren't many "undecideds" left to court.

More specifically, many voters think Biden is an idiot. No really, that was the second-most common word used to describe him in a 2012 Pew poll:

Which feeds into another reason:

He's a goofball
Sometimes, Biden's informality gets the better of him, and he comes of not as casual but as unprofessional, unpresidential.

Here he is during the State of the Union:

(via The Daily Dot)

And here he is reacting to Rep.Paul Ryan (R-Wis.) in the 2012 vice presidential debate:

This is the dangerous side of Biden's affability: While he has some serious swag, he also has a tendency to act like The Onion's parody of him as a bumbling, glad-handing, Fonz of a politician.

To wit:

He's a gaffemaster
Biden has a knack for boneheaded remarks, which would give an oppo campaign plenty of fodder. There's his offhand "big f--king deal" remark before the ObamaCare bill signing, or the time he asked a wheelchair-bound politician to stand up and acknowledge a crowd.

The gaffes are frequent enough that to find the latest one, you need only go back to yesterday, when Biden compared La Guardia airport to a "third world country."

He's old
If Biden won, he'd be 74 years old when he assumed office, which would make him the oldest person ever to become president. McCain was 71 when he ran in 2008, and age became an issue in that contest.

Biden could try to laugh off the age debate, a la Ronald Reagan, but late night TV would still have a field day with the occasional inopportune nap.

He's run, and failed, twice
Biden unsuccessfully ran for president in 1988 and 2008. Neither worked out so well.

The first time, Biden dropped out early amid accusations that he was a serial plagiarist; he was caught lifting parts of other politicians' speeches without credit, which led to the revelation he'd flunked a college law course for poor citation etiquette, too.

Then in 2008, Biden dropped out after winning only one percent of the vote in the Iowa caucuses. Sure, he got creamed by Obama's historic candidacy, but he placed fifth, putting him behind even the uninspiring Bill Richardson, among others.

That gets at the biggest problem facing a Biden 2016 bid:

P.S. Hillary Clinton
Yes, Clinton, is the most obvious reason Biden might not want to run. She has all the money, popularity, name recognition, and political connections to win the primary. There's also some sense in the party, whether justified or not, that it's her turn since she came in second last time around.

While polls this far out from the race aren't too predictive, they at least show how deep of a hole Biden would have to climb out from. The most recent ABC News-Washington Post poll gave Clinton a 62-point lead over the VP, the largest margin for any Democratic "frontrunner" in at least 30 years.