When I realized... what' I've missed

Coming from a foodsci degree, i thought i would at least have the advantage of knowing more things regarding food chemistry etc... then.. my supervisor
"yea.. think you'll need to do an ash test"
me: "ash...test?... how do you do that"
supervisor: "oh.. you guys never did ash test up at auckland.. go and see xxx technician and he'll sort you out"

so apparently... what they do is.. they burn the samples at super high temperature until literally everythign is burnt into ash.. then they weigh it.. and that's the ash content....

is it just me or did we.. never.. learn... that....

Then at class yesterday, we were talking about estimating costs and revenues for new products and stuff.. and the lectuere started talking about pay back period, discounted cash flow, total capital etc etc.. and i was sitting there with a million quesiton marks @_____@ then later on after class, my classmate commented on how boring that lecture was, coz it was a repeat of what they did in previous years........ hm..........