A difficult or trying experience; a hard time or task: While the ground crew didn't exactly have to carry me onto the plane kicking and screaming, it was no picnic/ It's no picnic, teaching people to play(1888+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with no picnic
Difficult, no fun, as in Recovering from abdominal surgery is no picnic. This expression, alluding to a picnic as a pleasant occasion, was first recorded in 1888.