Could be different types of buds which produce different types of highs... indica vs sativa for instance... one is a headie energetic high while the other is a zonk out sit-back-down-on-the-sofa high. Or did you say they were both from the same bag... I don't remember and I'm too high to scroll back up and read again haha. Also could be methods of smoking bong vs joint vs bowl as stated earlier. Or perhaps it's a first high of the day vs follow up highs thing. I know my first high is the best (which is why I like to save it til just before bed when the kid is asleep). I dunno man... just smoke it. hahah