OP: I had the same opinion as you, and I will say I did take it for a couple years (railed it, never smoked or IV) with occasional breaks for a week here or few months there for travel (at which point I never searched it out where traveled to or even thought about it till I came back), I modeled while on the drug, it never harmed me physically. Oddly my skin actually got radiant and smooth , but that may be because I was obsessively taking vitamins , like vitamins and taking care of it, because of what I'd heard about meth users. In the time I used I met a lot of people who also used (though I never hung out with anyone who used regularly and no one around me ever knew that I used).
They ranged from normal, business people, students and things like that to the typical tweakers you'd think of (kind of, not as bad, because those types scare me). I kept finding out that people I knew (and I am not white trash at all nor are the people I know) were taking it. I finished grad school while on them, and I also did a lot of soul searching I wouldn't have otherwise done to find things out and work things through I never would have worked through. It changed my life and while that doesn't mean I want to do it again, I am ultimately glad I did it for those reasons .
BUT
The first time I railed it I had a three day long psychosis. I won't go into that, it was actually what spiraled into my little need for awakening, because at the time I wasn't even sure if it was the meth that did it. I had no idea meth could cause what I saw, heard, felt and experienced those three days. It was intricate and I would like to point out that, I was logical and rational in every other way. So don't think your logic and rationale will save you necessarily. There were different species of beings there and I trusted some, was wary of others, refused to act on any info given either way. I didn't doubt they were real, but I did doubt something they told me and realized if that had happened Id find news of it online etc. I was thinking about how if it was true I could talk to someone about it without mentioning them because (except for one who I thought was just a person) I knew they wouldn't believe it and I didn't want to explain it. After that, I only hallucinated a couple more times, usually when I hadn't taken it in awhile (I would see mild things compared to that first time, which to this day I cannot neurologically, scientifically explain as being meth so I'm not sure if it was something else in what I took or even if it was real... but after that I only saw shit like ghosts or shadow people).
The last time I tried taking it after months being away was the last time. I didn't get euphoria, I got high (as in up), but that's when I realized I'd fucked up my dopamine. For me that was my biggest fear, and the reason I never planed to take it as long as I did. The time I was in the town where I was going to take it 'just while I'm here' kept getting rolled back further (due to unrelated reasons). So the 'I only have a week anyway, may as well' kind of spanned into half a year before I even realized. Ive dealt with trauma, death, tragedy (none drug related) ups, downs, I thought I had pretty much experienced the spectrum of human emotion and that there was nothing worse or better really. I was wrong. The empty, hopeless, nothingness type of numb is not like any numb I've experienced. After a day I wanted to kill myself (and I have really gone to hell and back in my life without that thought once crossing my mind) I thought I'd been through it all. Be sure you are fully ready for that. Cause I figured I would stop before anything happened, but time has a way of moving very slow (cause you are awake so long) and very quickly all at once. If I could go back I may have stuck to coke while I was where you're at . It doesn't do to your brain what meth does to your brain.
Also, the other difference is the way meth heads, all meth heads act. Unlike some other drugs (I think, Ive never tried crack or heroin) it doesnt make you do bad things for meth as much as it makes you think you are doing good things in general, regardless of the reality of what you are doing. Most meth heads have a perfectly logical, and often noble or self righteous, reason for everything they do, but they are also stubbornly aware of how crazy that reason would sound if you didn't know the context (aka the running track playing in their minds for weeks or months) I never got it either, and I would never steal or hurt anyone, I actually became even more empathetic on meth (and I was a bleeding heart already). But the paranoia.... oh the paranoia .... it creeps up on you, it becomes rational, you go visit family and think "do they know? are they going through my stuff? Why would they hide it from me, why not confront me?" .. its all plausible things (you are taking meth, they would maybe find it, they may not know how to tell you) that spiral steadily ...you ask them if they were in your things to give them an opening, sure your things are not where you left them -memory loss and some form of sleep walking while conscious often makes you feel things are not where you left them- and they still deny it, but you can see they are not telling you everything, they're lying -probably because theyre worried by your obvious demenour and distress- this goes on or awhile and they keep not telling you the truth, even considering that it may be because they are worried, you don't get why they wouldnt then tell you that...until you are going through your families things, not to find money, but to prove they are hiding something from you cause you want to know what it is (even though you are the one hiding something)
... I have never taken heroin.... but ... coke never did that....with meth things get weird. And then things get ...nothing...empty...hopeless. Is it worth it to you?