Efficiency is the process of "...choosing the optimum means to a given end (p. 36)". Efficiency is something that is sought after by many people, even without the shackles of McDonaldization. The difference is that in a McDonaldized society, efficiency is thrust upon a person, so instead of choosing your own methods of efficiency, you are forced to accept the efficiency of the surrounding institutions.
In fact this can lead to a lamb-like acceptance of what the surrounding institutions consider efficient. Which may be vastly different from what would actually be efficient for either the employees or the consumer.
Ritzer uses the examples of salad bars: in essence, with a salad bar, you buy an empty plate, go to the bar and create the salad yourself. This is very efficient for the restaurant, but makes more work for the consumer. In other words you have to pay for the privilege of making your own salad.
Another example of this inefficient efficiency is the ATM machine, popular at many banks. The consumer has to fill out all of the paper work, enter in the deposit or withdrawal to the computer, and, on top of all this, pay for the privilege of being a bank teller.
Many would argue that both the salad bar, and the ATM are conveniences, rather than inconveniences. With the salad bar, you are not limited by what the cook wants to put in the salad, and ATMs allow you to do your banking any time you want, unhindered by inefficient bank hours. However, keep in mind, that both of these serve to reduce the level of human interaction. Consumers are forced to deal with computers or salad bars and not people, training them to be better workers for the McDonaldized society.