Everybody's afraid of something. Whether it be flying, public speaking, spiders or the dreaded dentist, we all have things that make us squirm.

When that fear becomes strong enough and irrational enough though, it develops into a full-blown phobia. Of course, not all phobias are created equal; some are just more irrational than others.

It's pretty easy to understand how the fear of heights (acrophobia) or dying (thanatophobia) can fill somebody with paralyzing dread, but what about the fear of chickens (alektorophobia) or chopsticks (consecotaleophobia)? Guess somebody isn't ordering the cashew chicken.

All jokes aside, the National Institute of Mental Health figures that up to 18 percent of Americans suffer from phobias, so there's a good chance that you yourself are phobic of something.

So, as we explore five of the strangest phobias out there, let's just hope your particular phobia isn't pinaciphobia, or rather, the fear of lists ...

Llanfair train station sign

No. 5: Sesquipedaliophobia - Fear of long words

It took one seriously sick sense of humor to come up with the name for this phobia. Seriously, how can anybody who suffers from the fear of long words ever be expected to tell people what their diagnosis is?

In reality, there have been no actual documented cases involving sesquipedaliophobia, but the experts haven't let that stop them from identifying it as a type of anxiety disorder anyways.

One wonders how someone would even develop such a phobia. Maybe it would have something to do with an overzealous English teacher and an unfortunate spelling bee mishap?

But the word wasn't quite long enough for some jokesters, who suggested the 15-syllable hippopotomonstrosesquipedaliophobia instead. Just try to pronounce that one. Or, rather, don't. We're not waiting.

This longer version is a combination of the original phobia with the roots for hippopotamus and monstrous tacked onto the beginning: Literally, the fear of long hippopotamus monster words.

Frightening, sure, but not nearly as much as our next selection ...

mother-in-law closeup woman's face

No.4: Pentheraphobia - Fear of your mother-in-law

Most married people realize deep down that their mother-in-law isn't really out to get them ... although it can sure feel that way at times, can't it?

But while most of us leave it at simply not liking our mothers-in-law, there is a smaller group that suffers from the surprisingly common, although often unspoken, phobia of mothers-in-law.

Pentheraphobia can be caused by an intense negative experience from your past, but your mind can also create that fear seemingly without basis.

Then again, maybe that basis can be found in pop culture. There's no doubt mothers-in-law have been an all-too-convenient storytelling tool since the dawn of both television and movies. The ranks of overbearing matriarchs run the gamut from Mother Jefferson on "The Jeffersons" and Endora on "Bewitched" to Jane Fonda's title character in the 2005 theatrical flop "Monster-in-Law."

Of course, of the many available therapies for pentheraphobia, divorce seems to be the quickest and most popular method.