Those god forsaken counters.
You can't just say five pencils. You have to say
5 long thin object even-numbers-4-and-under-and-odd-numbers-5-and-over-counter pencil
Go hon enpitsu
The pattern for which is
Pon Hon Bon Hon Hon Pon Hon Pon Hon Pon etc.
They can't simply say the number of clouds the same way they say the number of machine presses. Or count small animals the same way they count apples. Or demigods the same way they count flat objects.
Small round objects and military brigades would obviously be counted the same way though. Obviously.
There's also a unique counter specifically for armed naval vessels and slices of fish on top of balls of rice.
And one just for straw mats.
And one for graves, CPUs, wreaths, and dams.
And while small animals and arthropods have one counter, and large animals have another counter, you count butterflies using the counter for large animals.
Oh and the first 10, 14th, 20th and 24th days of the month essentially have unique names.
I knew a native Japanese guy who spent 4 years mostly away from Japan, and he started to have trouble remembering the days of the month.
At this point for me, the measure words are actually a help instead of a hindrance when I encounter a new noun that I don't know -- it hints strongly enough at what sort of noun I'm dealing with that the context usually allows meaning to more readily snap into place. More useful than memorizing generic masc./feminine/neuter for most Indo-European languages.
(Assuming it isn't just like.. "parutikkuru akuseroreta" or something)
(Chinese is also much simpler when it comes to measure words)