Without lift the wine will feel flabby or flat, which means that in sparkling wine it has lost its effervescence and with other wines it means that the wine is low in acidity and does nothing but lay in your mouth. This is usually used when talking about wine that has been made with grapes that are not ripe enough.
These are measures used to give us a variety of flavor to compliment any palate. All these levels of structure can change a wine and give it the lift it needs.