Fear of long words.
Imagine the diagonosis...:
Doctor: Well son, we found out what you have...
Patient: Yes, doctor?
Doctor: You have Sesquipedalophobia.
Patient: Holy shit! That's a long ass word! I'm fucking scared and I'm going to go kill myself!
Doctor: Damn, I can NEVER get thru that damn diagonosis with ANYBODY. SHIT!
A better way of saying Hippopotomonstrosesquippedaliophobia.
Patient: Give me the diagnosis...
Doctor: There are two ways of saying this, but your not gonna like either of them!
Patient: I'm ready...
Doctor: you have Sesquipedalophobia...
Patient: DAMN!!!! Thats crazy! Get away from me!!! Say the other one, QUICK!
Doctor: you have Hippopotomonstrosesquippedaliophobia.....