What ignorance can do

The danger of living in the state of ignorance is akin to walking toward a tunnel not knowing that at the end of it is a dead end. Although in normal circumstances there are quotes that mention ignorance is bliss . But i found out now that ignorance is never a bliss for me.

 Sometimes when we had encounter some difficult moment and when we look at people who seem to know nothing and still live happily , a thought did arise that "at least they still can smile and live happily , for being ignorance and never knew the truth". But on other occasion i also came out with another conclusion, should one let say out of ignorance, eaten something or did something that causes the person to develop cancer for example. Would it have been better that the person aware about it instead of suffer the pain for years for not knowing ??? Which would you choose were you given the choice?

Ignorance also can happen in our daily life in almost all aspect of oue life. from daily eating habits , to making friends or even for not alert enough in our daily life with our surrounding that can causes danger into our life. 
Let just said that if you had ignorance about food expired date, you may end up seeing doctors for stomachache at the end of the day. But what about if you had mistaken a toxic pills as medicine pill?