Why in the world do....?

Question

...flies land on you-over and over and over-even after you swat at them when there are a million other places in the room that they can land?

Answer 1

coz on our bodies are millions of microorganism tat are sources of their food...

Answer 2

Our taste, smell, and moisture is just what they are looking for.  Face flies are actually going for the moisture in our eyes, they lay their eggs there.  We are not unique, watch a horse or dog, when the flies bother you they also bother them.