not be all beer and skittles

be (not) all beer and skittles

To be fun and enjoyable. This phrase is often used in the negative to convey unpleasantness. Primarily heard in UK, Australia. You've been working all weekend, so just come out with us for a little while—it'll be all beer and skittles, I promise. University isn't all beer and skittles—you need to take your schoolwork seriously.
See also: all, and, beer, skittle
Farlex Dictionary of Idioms.

not be all beer and skittles

BRITISH
If something is not all beer and skittles,it is not as enjoyable or as easy as other people think it is. Others are keen to make clear that City life is not all beer and skittles. It's not all beer and skittles when you get to be famous. Note: The game of skittles is associated with beer because it is traditionally played in pubs.
See also: all, and, beer, not, skittle
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • be (not) all beer and skittles
  • (all) beer and skittles
  • are we having fun yet
  • Are we having fun yet?
  • AWHFY
  • all it's cracked up to be
  • cat's pajamas
  • pajama
  • pyjama
  • the cat's pajamas