Three bars (6mg) of xanax is a rather hefty dose for someone with minimal tolerance. The high attained from benzos IS rather subtle on its own. But if you have anxiety problems or a panic attack, the instant, powerful relief is what many people associate the high with. Someone who isn't anxious at all, who takes some xanax won't be getting the same "relief" as an anxious person. Now, xanax certainly CAN produce a decent 'high'. It is a wobbly, drunk, inhibition-free feeling, often times accompanied by severe amnesia(especially at doses like 6mg) !
Many people also do not find that benzos produce any sort of wonderful "high". These are usually the folks who do not already have anxiety problems. In my opinion and experience with benzos (7 years of on and off addiction/dependence), they are best used as intended. Anxiety relief. Now, on th eother hand they do make for great accompanyment to other drugs, such as weed, opiates, stimulants, psychedelics. If you decide to mix with opiates, keep the doses of each LOW. Like if you have no benzo tolerance, combine .5mg-1mg with your opiate of choice to add to the sedation and nod. But exhibit extreme caution, as benzos plus opiates account for many overdoses/bad times so certainly DO NOT take 6mg and then rail some oxy or shoot some H if you have no tolerance.
There are many threads about benzos, using the search engine you should find a lot of quality information.