First, where I'm coming from: I'm an atheist, I don't believe in a god or gods. I can't prove one doesn't exist, but then I don't believe it falls on me to do so.
I have many close friends and people I love who do believe in God. And though I admit that I privately wonder sometimes how rational people can have religious faith, I don't begrudge anyone their right to believe in a higher power.
I think the idea of faith can be a comfort to some people, and help them get through difficult times in their life. If it does, than I don't see how I can dismiss it out of hand as a bad thing.
For me, the bad arises when the basic fundamental values we can all get behind (don't kill, don't steal, etc) are abandoned or perverted to serve some other more insidious goal (impose OUR values on YOU). Mostly I put this at the feet of organized religion. And I don't mean your mom's church and its bake sales, I mean any grand institution which is largely designed to get people to behave a certain way and share a certain set of beliefs. There's no need to go into the long list of misdeeds perpetrated in the name of religion, it's too long to count.
Mostly I have a problem with anyone who follows unquestioningly what a religious authority tells them. They got the don't kill part right, loving your neighbor is pretty good, but when they're also loading up ample portions of bigotry and xenophobia is when rational people should say "wait a second.." but too often they don't.
Faith is not a bad thing. Blind faith is one of the most dangerous forces in the world.
That's all I've got.