Why do some creams/fats whip better than others?
Cream itself is a colloid made up of butterfat &amp; water. That colloid is uniquely suited to have the air incorporated to create whipped cream. 

The chemistry of whipping cream is more complex than just "fat + air = whipped cream". If you're trying to whip olive oil or lard into "whipped cream" then each fat will have some unique additional steps to make it hold the structure. 

For example, adding a dash of acid and an egg yolk (which contains lecithin, an emulsifier) to olive oil will help create a colloid when whipped. In this case, the resultant colloid isn't whipped cream though--it's mayonnaise.