Q:

Why is it bad to have an inductive load (context: dc-dc converter)?

In the book I'm studying from Power Electronics - Mohan he says:

(...) has two drawbacks (1): In practice the load would be indictuve.
  Even with a resistive load, there would always be certain associated
  stray inductance (...)

This is in reference to a basic buck converter where for the sake of simplicty he explained the operation using a very basic circuit:

Then, he said what I just quoted. He said that an inductive load is a drawback. Not only here, but in previous chapters they speak contemptuously about inductive circuits in general. So, my question:  why is it so bad to have an inductive circuit or an inductive load in general (they can't be bad always, can they?)?

A:

It's actually an issue with reactive loads in general, although inductive loads are the type most commonly seen in industrial applications (lightly-loaded motors, etc.)
With a resistive load, the current always has the same polarity as the voltage, and this assumption vastly simplifies the design of power circuits in general.
With a reactive load, the inductance or capacitance sometimes returns energy to the source, which means that the current can have the opposite polarity from the voltage at times during the AC cycle. This is much more difficult to handle in a power circuit.
Sometimes it's well worth the extra effort — for example, in an electric vehicle, the same power circuit can handle driving the motor from the battery as well as the regenerative braking.

