You are exactly right. My sister asked me years ago how I felt when I took my xanax, which I started taking in 2011 after I had a brain aneurysm and was in neurological ICU at Shands in Gainesville FL for 8 days, I said I feel normal. She's a former nurse and replied with "well then, you're taking it for a valid reason". If the drugs don't change the way you feel then like pain meds, if there is pain there to kill, you'll feel normal. If there is no pain to kill then you get that high and that's what keeps people coming back and needing more to experience that high because their body got used to the dosage. The urine test that my doctor does every visit tells him the level of medication in my system. If it's more than what my RX is for, he'll know I'm taking more than necessary. If it's too low, he'll assume I'm selling them so those urine tests are for more than looking for other drugs you have no RX for. They are to make sure you are taking your meds as prescribed.