1.The Food.This could also be reasons 2-10 but that might make me look a bit gluttonous. I say this as someone who, ironically enough, could not eat about 70% of what was on most menus. Island cuisine=lots and lots of seafood. But the things I could eat, particularly the papas arrugadas (or wrinkled potatoes) and the tortillas Españolas were more than enough to keep me fat and happy. Add to that the tapas, usually marinated olives or homemade chips, that came with every drink and it is a miracle I did not roll off the island.
2.The Public Transit. For three days, we stayed in the capital city of Las Palmas. I briefly considered renting a car to explore the surrounding areas but once I took a look at the bus schedule, it was clear that there was no need. Public buses frequently do the loop around the island in either direction, making it easy to get to anywhere you want to go, usually without transferring.