Bees in the bonnet are no fun. Here are some basics about bugs:
Mosquitos: Along with gnats, midges, and black flies, they're out for your blood. They are attracted to carbon dioxide, lactic acid, and warm, moist air--all the things people give off as they walk or move around outdoors. Repellants and protective clothing are the only thing that deter them.
Thicks: They wait in the bushes or tall grass for you to come along. Once on board they take 6-8 hours to really latch on, even longer to start feeding. They can transmit some serious diseases including Rocky Mountain spotted fever, Lyme disease, the tularemia. Before walking through a tick-infested area, put on light clothing (so they'll show up) and tuck long pants into boots or socks or ware gaters. At home, check your hairline carefully; it's their favorite feeding area. If you find a tick or your body, grasp it with tweezers close to the skin and pull it out firmly and steadily; then disinfect the area and wash your hands.
Wasps: Exhibiting the same behavior as hornets and yellow jackets, they're not out to get you, but they will sting if you interfere with their nesting or feeding. Avoid looking or smelling like a flower when you go out walking. If you get stung apply an ice cube or a baking-soda-and -water paste.