  Astrophysical fluids, including interstellar and interplanetary medium, are
magnetized and turbulent. Their appearance, evolution, and overall properties
are determined by the magnetic turbulence that stirs it. We argue that
examining magnetic turbulence at a fundamental level is vital to understanding
many processes. A point that frequently escapes the attention of researchers is
that magnetic turbulence cannot be confidently understood only using "brute
force" numerical approaches. In this review we illustrate this point on a
number of examples, including intermittent heating of plasma by turbulence,
interactions of turbulence with cosmic rays and effects of turbulence on the
rate of magnetic reconnection. We show that the properties of magnetic
turbulence may vary considerably in various environments, e.g. imbalanced
turbulence in solar wind differs from balanced turbulence and both of these
differ from turbulence in partially ionized gas. Appealing for the necessity of
more observational data on magnetic fields, we discuss a possibility of
studying interplanetary turbulence using alignment of Sodium atoms in the tail
of comets.
