Alright... even on my old account I never went too deep or told anything about my own story, but here it might just help with some insight.
Just be careful big homie, I also have smoked both crack cocaine and meth, I have IV'd both once wondering why the fuck it wasn't working, having been with the smugglers (in the case of the coke not the meth) hours before it even hit our shores, being Australia Meth grows on trees here. I was with a girl and she had been an IV user up until this point I was not aware. So, apart from my own training there was an old associate of mine who happened to IV and have been a nurse, I count my self lucky feeling a rush of sickness and nothing to powerful, the smoked high genuinely felt more potent to me at the time and I preferred as fucking crazy as that may sound. Thankfully I haven't used uppers in years and the urges have and never do take me over even when a pile of coke is in the same room as me but id never count my self out of a offer of a good time on the rare occasion.
When I was using the cocaine and crack I found it incredibly social and managed to never manifest it further like most of those who did it with me at the time did or still do. As for meth I found it my go to aphrodisiac with a girl and thankfully never went into using it on my own and building these deeper addictions. My ROA (smoking a pipe for the meth and snorting and smoking for the coke and crack) Other than the 1 time IV each substance I never deviated much. I also felt un-addictable if you will but that's some bullshit, even if you never increase that use its warping your dopamine pathways enough that I can promise you, you almost certainly are not the person you'd be off it even if subtly. Now while no one could or did ever in hindsight know or even think I was touching these substances and my parents lived their lives on speed. The one and only real issue I still have is pervasive dreams mostly of smoking a pipe of either substance and fucking. I thankfully never fall to those cravings I never had to get rid of a dealer or do anything special to kick it but that occasional intrusive thought even if it isn't to reuse and it rarely if ever is still comes back reminding me just how great sex was on it. While not at all thankfully ruining it post as I didn't do it to often (most a few times a month at worse maybe a week for a short period).
I wish you the best and myself can sustain a doctor scripted pain management dosage of very powerful opiates and occasionally equally as powerful benzodiazepines, despite my decade plus of every day usage of something or another if not damn near close to it (Even though I'm 100% a downer person any day over any upper). I have come to terms with the few DOC I shall keep in my rotation and as to where the benefits out weight the negatives, and this be the opinion of multiple medical professionals and they are not dodgy doctors I must say. Such as weed and my pain medication, and even though I prefer downers to get me a high if it comes to it, id really fucking kill for good LSD or Mushrooms when its been to long since I can get them, but that's always more like a kid on Christmas thing than any other drug urge feels like. Point is all these years later I still have moments I remember from the pipe that I could see alluring most people back, not so much using it, that's more part of the invasion on the dream, (thank fuck its not enough to get me to ever seriously contemplate going back to it), and as good as some times can be on it, as much money as it may of made me, without them I'm in everyway better off and more successful objectively looking at both situations. Financially and most importantly mentally and I thank my fucking lucky stars I don't have to spend every day slaving to or running from an addiction knowing I could feel better than I do now because I have what iv spent a decade plus setting up and securing.
I understand everyone is different and not the same with drug reactions but you describe yourself as very similar to me, naturally very cheerful, optimistic, and able to push through some real shit almost unscathed and without reaction. The mental wealth you speak of is indeed far more important imo at least in the fight against forming addictions but it goes far deeper than that. That being said I wish you the best and hope you stay uninfluenced by dependence or any sort physical or psychological.
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. I am semi-functioning with my addictions, have been for 10-15 years but I am getting to a point where I need to quit or get my shit from a doctor because I want a better life. Crack was the only drug I hadn't tried yet so my reasoning is its better to have my fun with it while I am not "rich" or well/better of lol. 
