FL, being a swamp with lots of water and stuff to eat, has a vast, almost incomprehensible, array of annoying flying insects.
In addition to the already mentioned gnats, house flies, horse flies, and mosquitos we have a particularly aggressive version of a biting yellow fly that makes a horse fly bite pale. Those little bastards are also seemingly immune to all repellants and insecticides once grown. We also have tiny little biting flies called No-See-Ums, which, as the name implies, are hard to see but love to swarm anyone that is hot and breathing hard (they like CO2).