Most people aren't crazy about methylphenidate. I, actually, do really like it, and at doses not yet exceeding 20 mg via insufflation; I refuse to take it, orally, which is weird because I almost always go for the oral route of administration for other drugs, due to generally good bioavailability, but I know I get more out of insufflation, and I enjoy the speed at which this particular euphoria hits when insufflating it. I have had ample experience with amphetamines, and can definitely understand why someone would prefer an amphetamine over methylphenidate for a good deal of reasons, but, at least for me, methylphenidate has a special place in my heart. Amphetamine euphoria is quite different than methylphenidate euphoria, in my opinion, so I certainly appreciate both. But, if you are not experiencing any notable euphoria at doses of up to 40 mg, especially taken via insufflation and rectally, I wouldn't go on trying to chase the high you never really had. Some people straight out dislike methylphenidate's effects; even if you aren't one of those people, you don't sound like the fairly rare ones like me who can get very excited over some methylphenidate, so again, don't go on upping the dose - it won't lead to anything good, I can say almost certainly. Is it your ADHD? No. Stimulants don't somehow act differently so as not to produce euphoriant effects for those with ADHD - they can help the symptoms of ADHD, but the effects are not dependent on that diagnosis, however different PEOPLE can and do have different SUBJECTIVE EXPERIENCES with the same drug at the same dose. So, it is not just you, but methylphenidate doesn't suck for everyone.