Culinary uses of olive oil vary from country to country and from Chef to restaurant. Let alone how moms and grand moms use it.

Olive oil is the main cooking oil in countries surrounding the Mediterranean Sea.

Extra virgin olive oil is mostly used as a salad dressing and as an ingredient in salad dressings. It is also used with foods to be eaten cold. If uncompromised by heat, the flavor is stronger. It also can be used for sautéing.

The higher the temperature to which the olive oil is heated, the more one should prefer the use of refined olive oils. When extra virgin olive oil is heated above 350 °F (177 °C), the unrefined particles within the oil are burned. This leads to deteriorated taste. Also, the pronounced taste of extra virgin olive oil is not a taste most people like to associate with their deep fried foods. Refined olive oils are perfectly suited for deep frying foods and should be replaced after several uses.^{[citation needed]}

Choosing a cold-pressed olive oil can be similar to selecting a wine. The flavour of these oils varies considerably and a particular oil may be more suited for a particular dish. Also, people who like lots of tannins in their red wines might prefer more bitter olive oils.

An important issue often not realized in countries that do not produce olive oil is that the freshness makes a big difference. A very fresh oil, as available in an oil producing region, tastes noticeably different from the older oils available elsewhere. In time, oils deteriorate and become stale. One-year old oil may be still pleasant to the taste, but it is surely less fragrant than fresh oil. After the first year, olive oil should be used for cooking, not for foods to be eaten cold, like salads.

The taste of the olive oil is influenced by the varietals used to produce the oil from and by the moment when the olives are harvested and ground (less ripe olives give more bitter and spicy flavors, which is a positive attribute – riper olives give a sweeter sensation in the oil).

Olive oil has more uses than as food; it also works as a natural and safe lubricant, such as lubricating the machinery that is used within the kitchen (grinders, blenders, cookware, etc.)

Source: Wikipedia