I totally get that feeling. You come to the drop after making a bomb ass intro, but you lost all motivation to make the drop so you either just say fuck it and trash the draft or you half ass the drop.
Earlier in my producing years I often did the same thing, ESPECIALLY with dubstep. What helped me is just making the drop first, and then making the intro, then the buildup, all in that order.
Don't make an intro if the drop sucks. Wait until you make a drop that exceeds most of your other work, and then still your guts to make an badass intro, and hype buildup.
It might take a while to get used to, but that tip alone helped me more than anything in over all the time I've spent producing.