Were we really that stupid when we were that age?

Today, i had the absolute joy of teaching my favourite 5nensei at Yamada Elementary... NOT! i swear to God they shit me to tears. It makes u wonder what we were like when we were that age.
Today i taught the kids the phrase "How old are you?". Simple enough right. We went through numbers, did a quick game and then went to the main activity which was BINGO. Now, kids here do bingo quite a lot but this was a little different. I made a sheet with nine faces on it, leaving one in the middle blank for the students to draw in their own face. under all the faces was written "I'm _____". I told the kids, after desperately trying to get their attention, to just write their favorite number from 1-12 under their own face. Then i told them to draw their own face. I repeated the just write a number only under ur own face about 5 times and there were still some retarded kids who wrote a number down under all 9 faces!!! DAMN MONGOLOIDS!! how hard is it to follow instructions? i did the same class almost with the 3nensei and they grapsed the whole "write under only ur own face" concept that i had told them time and time again.
Hey, i know this is only a small thing but knowing i have to teach those damn 5th years on monday mornings puts me in a shitty mood for the rest of the day! hehe