In return for the trouble one has taken, as in And all he got for his pains was a failing grade. This expression is nearly always used ironically to indicate that the return was not appropriate to the effort made. [First half of 1500s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.