there are at least 2 perfect answers here already, but a couple that characterize turbulence inaccurately as dangerous. just to add another view/definition, turbulence is weather-you are flying through the air, and as such the air that is holding you up you can feel-if there is rougher weather, you feel it more.
on with the rebuttal: no airliner has broken up due to turbulance. incidents that have occured would have been in cheap, poorly built planes, and the cause would have been the plane-not the turbulance. they regularly fly planes into tornado's on purpose to study them. in fact, usually lockheeds, who also build airliners. and boeing has an even better reputation for strentgh. boeing does strentgh test by physically breaking wings off: and it takes much more force than any wind or air can do.
as for the loss of control: this is referring to smaller, lighter planes getting caught in the wash left by larger airliners, or planes running into mountains from turbulance. but no pilot is going to fly a passenger plane close enough to a mountain to even be close to a risk, and also there are laws stating how close planes can follow each other according to size. i don't think they even have statistics on it, but it would be far, far, less than the statistics of crashing in a plane (i'm sure you know how about those statistics). i bet it might be at the bottom of all incidents, if at all.
last thought for comfort: there is nothing to crash into in the air, and the planes will NEVER break apart, and the air that holds you up will never, ever, go away. it may seem magical, but it is science. you can not fall out of the sky. and in the event something did happen, being up in the air, the pilot has a lot of time and warning to compensate-again, the air is not going away and there is nothing to crash into.