Beachn…..You ask why....and, say that you don't "get it"......which it is natural, I think, to wonder the "why" of things that don't make sense to us.....
Especially, for something that one has not actually experienced, for themselves. For the non-addicted, who have never had all of the neurotransmitters, in their brain, totally rearranged....which has effects o n cognition, emotions, memories, impulse control, etc....
It takes about 6months, on average for the heavily addicted to begin to just clear their brain....and, much longer to address underlying issues....
To answer your question of "why?"....I think it might help you to understand what you can't actually see.....
I would recommend the following books....for a deeper understand ing what actually occurs within the brain....and, be able to connect that to external behaviors....
1. The Addicted Brain--by Michael Kuhar…
2. The Science of Addiction---by Carlton K. Erickson
***this one is a bit more technical than the first one...
Both books contain the latest research on addiction
Both are available on amazon.com....and cheaper, if you order the used copies....(they are similar to textbook prices)….
Knowledge is power.