Their handwriting are illegible 100% of the time. You look at that handwriting that looks like a wriggling snake. You try to figure out which is the 'a's or the 'e's.

My classmates and I were impressed by the fact that somehow nurses and pharmacists can understand them. We thought, "Well, they just take a look at the prescription and AGAR guess the name of medication from the looks of it.."

From there, we deduced that doctors themselves can't remember the spelling of the complicated names of medication and diagosis. Hence, the atrocious handwriting to conceal their inability to spell.