That's actually a matter I used to struggle with. The pastors and professors kept describing this vision of Heaven in which all we would do is "be with God," and "worship him eternally." I have to admit, to stand around for eternity worshiping goes against my core personality. To me, having my free will removed and being reprogrammed to eternally worship God would be a massive violation of my free will. If My personality is left intact, and only my behavior is changed, well then, that sounds a lot like Hell to me, not Heaven. If my personality is altered so that I will want to eternally worship God, well then I won't be me anymore, will I?
So it seems that in the traditional version of "Heaven," I will either be locked eternally inside of a body that no longer follows my instructions, or I will have my personality rewired and my mind wiped.
Usually my doubts have been "helped" by a "helpful" Pastor who explained that in Heaven I will be "restored" to perfection, and I will want to do nothing but eternally worship God in joy and adoration. I have to tell you, that really doesn't sound like me. I would want to talk with God, to ask him a butt-load of questions and then I would want to exist in a world without all the violence, hatred, and sociopathic insanity we live with on a daily basis here.
If I can't write in Heaven, then that would make it Hell. If I can't read in Heaven, or if the only thing I can read is the Bible, then that would make it Hell. If I can't paint or draw, if I can't play games with my friends, if I can't pet my cat, if I can't make love to my wife, if I can't sit and think quietly by myself, if I can't determine my own path, well then that would be Hell. Lakes of fire and eternal torture are nothing compared to having your core identity redone to fit God's idea of what you should be in "perfection." Change me to that extent and I'm not me anymore, so I'm not in Heaven, some other guy who looks like me is in Heaven.
So now I believe that Heaven is not, in fact, the eternal adoration the hard-line Christians believe it is. I'm not sure what it may be like, but I'm pretty sure that it won't be an endless Elysium Field of robotic worshipers chanting God's praises forever. After all, if God had wanted humans without free will, if God had wanted robots, then he would have created Adam and Eve that way, wouldn't he?
Many Christians forget that according to the Bible, Adam and Eve were created "perfect" in the Garden of Eden, and they had free will. They did not spend every waking minute worshiping God. Hell, they even defied God. And if they were "perfect," then it stands to reason that in Heaven you will also have free will, since having free will is part of being a "perfect" human being.