Storm in a teacup -  situation where people get very angry or worried about something that is not important (The Free Dictionary); petty disagreement, fuss about something of little importance (http://users.tinyonline.co.uk/gswithenbank/welcome.htm)

Example of usage: I think it’s all storm in a teacup, there’s probably no danger to public health at all.

I chose this as my first idiom to feature because I often hear this expression used at work. In my job, I deal with a lot of incidents that can be painstakingly stressful, sometimes a lot of fuss is made that would usually end up to be not necessary at all. But since we can’t take chances, we are bound to always come across storms in  teacups.