"Nagative:

"If God has already decided who will be saved and irresistibly calls them, does it really matter whether I witness or not?" This was the logic of those who told William Carey, "Sit down, young man! If God wants to save the people in India, he can well do so without your help."
William Carey himself was a Calvinist."

Those who said that to William Carey obviously were Hyper-Calvinists (or at least in what they said), not Calvinists. So obviously this is not a negative as far as Calvinism is concerned.

Actually about the only negative that I can think of is Calvinism comes across to many as unfair. But in actuality, that is only because the person who thinks that is looking at the issue through their own selfish perspective, instead of through the perspective of our sovereign God.
This is one of the things that made it so hard for me to embrace Calvinism. At first when I was confronted with this truth and couldn't wiggle out of what I saw Scripture teaching, I tried everything I could do in hopes that some how Calvinism was wrong. Not to mention the fact that I knew what many of the people that were close to me would think about me embracing Calvinism.

Even after I embraced Calvinism, it took quite a while for me to see the matter through the eyes of my sovereign God. It was almost like getting the scales removed from my eyes.

Sorry guys for rambling.

Tom