What is the absolute #1 thing you could recommend to me? Why?

Question:

What is the absolute #1 thing you could recommend to me? Why?

Foods, restaurants, gizmos, books, places, lessons, anything etc...

Best Answer - Chosen by Asker:

Oxygen. Without it, you would die and the others would be meaningless. You need air first and foremost. It is one of the few luxuries the tax office has not touched!