Good reasons to start vaping:
1) Your dying of cancer.
My daughter decided to take up some light smoking while dying - she smoked about three cigarettes a day, I still have her lighter. So, if your dying of cancer and feel the need for an external stress reliever I'm sure your dad would not worry much about some light vaping.
2) your morbidly obese.
Nicotine can be an appetite suppressant plus it gives you a hand to mouth habit to give you something other than food to stick in your mouth so your dad, along with your doctors advice, might see vaping as an acceptable thing under such conditions.
3) Your bedridden and are tired of puzzles, and there is no one left online to debate.
4) You've smoked for 30 years and have no other way to rid yourself of the horrific addiction of smoking.
I'm sure your dad, along with your doctors advice, would see that as an acceptable reason to start vaping.
5) You want to be the guinea pig, unpaid of course, for the long term dangers of vaping.
Will it cause cancer? What kind of breathing problem will it give the never smoker in the long term? Just how addicted will the never smoker become?
All these things and more science would like to know where concerns the never smoker, and we lack a large pool of unpaid test subjects. .. we have theories of course, but no real world data. You would be doing the world a favor..
You might could talk your dad into allowing you to be that person.
hopefully this helped you In your search for valid reasons to begin vaping.