Because he could convert water into wine.
The wine producers weren't able to compete against someone who had basically no costs, and the rulers weren't able to find a legitimate way to tax the wine, so they decided that Jesus had to be eliminated.
I know you're being flippant but the reality is that growing up with the myths and stories surrounding Jesus I think in some ways desensitises people to what is being discussed, imagine that you were a community leader, wine maker, fisherman, physician, any of the other professions incidentially mentioned in the bible and you witness or hear of these miracles, its not simply going to be a joyous occasion or wonderous, especially not if you've also heard that Jesus is teaching something different to you or does not meet with your own and time honoured thinking or expectations.
They were as wary about false prophets, charlatans and cults back then as we are today, I'm pretty sure of that, having read the bible and studied similar sources, like Josephus, these were not a bunch of fools, credulously recording hearsay as the conceited present would have anyone believe. They were learned and cautious.
In many ways I can understand the Pharisees, Sadducees (spelling) and Scribes reactions to Jesus, I'm sure they were typical of their reaction to many others like him, but the difference was that physical or natural laws didnt need to matter a damn to this guy into the bargain. Even before he'd raised people from the dead (which he did with one or two others, although he suggested that they were not dead but sleeping and there's a possiblity, although it could simply be modern doubt, that this was literal rather than metaphorical, although I believe there were wake periods observed and they seemed pretty wholly dead in that time) and then raised himself, apparently, he's bound to have appeared pretty unstoppable.
There is also the element which was brought out in some of the more recent novelisations about the life of jesus (I say recent, it predated Mel Gibson's movie and was probably in the ninties) that Judas was a bit of a kind of marxist-leninist character, and perhaps some of the relgionists in the establishment were too, they expected a warrior king, this messiah talked peace but could be provoked, as he was by the money changers in the temple, and had miraculous powers. I'm sure they thought that by their actions they would be provoking a final confrontation, forcing Jesus' hand, so he would use his miraculous powers against the Romans. I'm sure there were plenty of people who, like you say, just wanted rid of him too.
The whole thing is an epic story about how no matter how awry the world has gone God will not destroy it, there will not be another flood, that violence and power can not conquer for good in the way that mankind has perrenially believed that it can.
