In my experience, every smoking method has a slightly different high. Why this is? I don't think we can say for sure, but it is definitely one of the interesting things about weed. Now I got really good at rolling joints and I could take huge hits off them, so I dont think I was necessarily getting more smoke a time with a pipe. But here is how its different to me.
Joint - smoother high. Tends to creep on you. I don't feel it much right away, but a minute after Ive finished the joint I notice I am ripped and still getting higher, then the high plateaus for a bit and then trails off.
Pipe - The high hits me right at the start, even before I can finish smoking the bowl sometimes. It is more disorienting like the OP said, peaks right away often with good euphoria but then trails off sooner. It feels much more "jagged" as opposed to the smooth joint high.
A bong is different still, but I havent used one in so long I cant describe how any more.
Anyway, there are several differences between a joint and a pipe. Who knows which accounts for the difference in high? But it could be some or all of them.
- As has been said, with a joint the smoke is filtered by the plant material in front of it.
- A joint may burn at a different temp
- depending on your personal smoking style, you may be taking different sized hits and or taking them at a different rate
- with a pipe, you have old resin trapped on the inside of the pipe which may influence the high (assuming the pipe has been used before)
- psychological, it is true that your expectations can influence the high
I dont know which of those reasons cause the differences, but I dont believe it is just psychological. After all I didnt expect the effects to be different. I think a joint is far and away the best way to smoke, unless youre a newbie and just want to get blasted by a bong.