Productivity heavily correlates with intelligence, so there is no "smart but lazy," there is simply lazy, as it is not intelligent to be unproductive.
What I want you to think about is why do you have to prove you are "smart?" What do you believe "smart" is? What do others believe it is and why should that matter to you or anyone else whether or not you are "smart?"
Why do you not point out that intelligence is largely influenced by genetics and social conditions, things outside of a person's control? Why do you not recognize that if we are to measure someone's worth on intelligence, that degrades people on the grounds they were 'born wrong?'
You spent your time in high school and college smoking weed and playing video games, which is a very unintelligent thing to do. You didn't 'already know everything,' you had passing familiarity with what you were taught between naps. But you being unintelligent does not in any way mean you should be subject to the now much higher possibility of being evicted from your house, subsisting on a diet of dried out, leftover white rice and still having to live paycheck to paycheck, or dying frozen on a sidewalk. What could have possibly been so bad about not wanting to do your trigonometry homework for you to deserve such disgusting negligence?
In the discussion of schooling or IQ tests or other things of a similar nature, avoid trying to convince people you are "smart," because you are not. Rather, what you should ask is "Why am I considered a lesser person because I am not smart?" Because you are not.