I know what you mean when you say that there is an element of control involved in a trip. Whenever my friends and I indulge we always make sure there is a suitable ambience for the "voyage". i.e music, lighting. The only downer in this situation is that sometimes just when you're suitably immersed, you need to go to the loo and thus interrupt the flow of things, so to speak!
When I talk of abuse I'm more referring to the worrying trend of the day of people not just taking drugs (and alcohol etc,) for a good night out, but taking bucketloads of things...way more than is "safe" or needed for an effect. You hear the stories of people not just taking things but guzzling stuff (22 E's recently reported for one wreck-head) to the point of desperation. Personally, I find this a bit much, whatever your poison is. For me, this seems to go from socialbility, or seeking an experience or even just a laugh to basic fucking yourself up.
I am aware that tolerances to certain things build up with regular use, but I do worry about the sheer volumes you see people taking and/ or drinking. Call it self-abuse if you will, but I think it can act as ammo for the Daily Mail brigade when some of the stats on the quantities some people do start rolling in.
There was one classic quote recently on the local news that made me laugh though: The report was on the fact that "the kidz" no longer seem to drink to be sociable but to get arse-quakingly pissed.
A hapless reporte asked a group of Ben Sherman scrotes "So lads, why do you drink so much when you're out"
Scrote reply in best nasal Manc accent "Takes the edge off the E's like". Priceless!!!!