| If you happen to live in Israel, you surely know that everyone is required to join the mandatory army service, at the age of 18 or after finishing high school--whichever comes last. You are first summoned at the age of 16 to take several writing exams and physical evaluations, after which your IDF (Israeli Defense Force) profile is set. The highest profile is 97, meaning you're in excellent physical condition.
The profile of 21 relieves you from the mandatory service and is 'awarded' to those who are able to convince an army psychologist that they are not qualified to serve due to a psychological (and sometimes physical) condition. Most people who receive a profile of 21 claim to be insane and actually manage to provide proof to that claim.
For most men, this is the only way to avoid being drafted. Women on the other hand can simply avoid the mandatory army service by refusing to join. After which they are threaten to be tossed into jail, but when the day finally comes, they just receive a letter which relieves them of their duty.
Unfortunately, the army doesn't just give out the profile of 21 to anyone who seeks it; in fact, you'll probably be thrown into jail, repeatedly, until you give up. To avoid this, one must convince a psychologist that he is capable of hurting himself, and will do so under the given circumstances. If you pick that path, you'll forever be tagged as insane and will have a hard time living in Israel.
Having a profile of 21, you can forget about governmental jobs, and issuing a drivers license will prove difficult.
Why would people refuse joining the Israeli mandatory army and agree to such harsh penalties is a whole other story, but many do, and this is the price.
Update: After missing my recruitment day; being drafted anyway; having been to jail (though only for a single day); several sessions with an army psychologist; and after bringing my mom there (apparently, a standard procedure), I received a profile of 21. Go me. | 
