What is the purpose of the tonsils/adenoids? Why would it be a good idea to have them removed? Why would it be a bad idea to have them removed?

The term tonsil commonly refers to a pair of deep pink
structures, one on each side of the back of the throat.  However thse are only one of
three types of tonsils. These are called palatine, or faucial, tonsils.  The two other
kinds of tonsils are the pharyngeal tonsils and the lingual tonsils.  Pharyngeal
tonsils, commonly called adenoids, are located in the back of the throat near the nasal
passage.  Lingual tonsils are located at the back of the tongue.  These three types of
tonsils form a continuous ring around the back of the
throat.

The purpose of tonsils is not known to scientists
with certainty, but many medical scientists believe they aid in protecting the
respiratory and digestive systems from infection, by being the first tissues to
infection in the digstive and respiratoty tracts, and in this way alerting the body
system to fight the infection.

Sometimes the tonsils become
badly inflamed and must be removed by a surgical operation.