This is why I believe the idea that different people have different levels of addictiveness(? not sure of the correct word). While one person may get addicted to something after a few hits/days of use, someone else may be fine doing it even more and have zero issues quitting immediately.

I'll use weed as an example. I lived with drug dealers (well, soft durgs--just weed) in college. Smoked basically every day for a year since they offered and hey, it was college. I never felt any "urge" to smoke nor did I have any issues quitting. I haven't smoked in years now. However, I have friends who can't quit smoking because they lose sleep, get anxious, or otherwise have mental issues such as those when trying to quit.

I'd assume it is similar to many other drugs. Alcohol is another example. In college I drank a lot. Eventually, with friends (both online and offline) I found myself having a drink most nights. Some nights it might be a few cocktails, other nights it might be tons of liquor/shots.

That lasted a long time, and my family wasn't any help--they drink every night, and my dad is basically a functional alcoholic (but doesn't drink during the day if he has work etc.). With them, I'd also drink basically every night. However, I recently went almost a month without drinking... and never felt any urge or want to drink. It was basically just like not wanting soda or something. However, me brother is an actual recovering alcoholic (like 4 months clean? not sure) that wasn't functional. Thus, this is why I believe that everyone has a different level of how easily they get addicted to stuff.