I was practicing right seat flying with a CFI in a
Cessna-150.  Although it was night and there was a 8
knot crosswind, my CFI told me to drop the flaps to
40 degrees for the next landing.  I explained that
I don't use 40 degrees for night and even in daytime
used them only when "landing is assured."  He convinced
me to put them to 40 for the landing, and then called
for a go-around at about 50 feet AGL.  Confused, I
applied power very late, took out the crosswind correction,
and forgot the flaps.  The CFI took the controls,
and the plane hit the runway, bumped the tail, and swerved 
to the left.  The CFI then recovered for the crosswind 
and pulled the flaps to 20 as the plane limped
in ground effect.  After landing we found the tail
fairing was cracked, but could't determine if it
was from this impact.
  I told the instructor later that I found that series
of events uncomfortable, but he seemed unreceptive, so
I stopped flying with him.