What are the issues you face when you access public wifi?

The biggest issue I face is the privacy concern  and hence, I prefer not to use sensitive information like my credit card number, accessing social security accounts or important documents while I am connected to public wifi. I still feel very comfortable using an airport Wifi because somehow I feel that it should be safe since a lot of passengers are present and if the data is leaked, that will impact the prospects of airports. 

Any other precautions you think I should take?