[tedunangst]

Breaking stuff is still a good way to viscerally understand that tiny mistakes are fatal. Crypto that looks good turns out to be useless. The best way to really internalize that lesson is to see the crypto die. (I don't think it's strictly necessary to work through every example; looking at the problem, then reading the solution is probably good too, but one should spend some time looking at the problem, enough to say "yeah, this looks good" before watching it burn.)