I never experience this so called euphoric and sudden rush when smoked either. Its more of a gradual come up... I get a body rush "sometimes" when I take a good hit and hold it in deep and long, my heart races, head feels light, eyes throb, and my chest feels warm... But never a mental rush of
meth effects...
And Im not an IV user, so I may not be able to provide as good insight as an actual needle user can, but I can at least share with you what I've gathered from my research and what not...
Meth varies from batch to batch so much compared to other
drugs. Some certain batches may have more effective ROA's than another batches. Generally speaking, its a good rule of thumb that injected meth produces a more noticeable, distinct, and stronger come up or rush than when smoked... Smoked more so than
snorting. This is a rule of thumb however, and while probably true for most batches, doesn't necessarily have to be true. Perhaps your batch is better off smoked. So to answer your question, no I dont believe slamming meth absolutely HAS TO be the best route of administration for every batch of meth. You did mention though that others are "ga ga" over this meth... so...
The individual plays a big role. Some people aren't as affected by certain ROA's as they are others whether with drugs in general, or even uniquely to certain batches. Personally, snorting drugs has never been an effective ROA for me, I'm much better off smoking it. But you seem like you have injected before with positive results, so this might not be an issue with you.
Also, the current mood your in, and the technique you used for injecting could have given you a different outcome than what was expected. Im not saying these WERE factors, you could be a pro injector extraordinaire for all I know :P
All in all I think its the first factor I mentioned.
It's hard to say, and could easily be a reason that I didn't mention, or a combination of several different reasons, and it's gonna be hard for even an IV expert to pin point exactly why that meth seemed to work better smoked for you. If I were you I wouldn't draw any conclusions about the meth based off of that one experience...