Best laid plans

[Sonia]

The full phrase is
the best laid plans o mice an men gang [aft] agley
This was written by an ancient [Scots] Poet, [Robert Burns], who wrote several poems in a strange language, including To a mouse.
Gang aft agley means often get fucked up
best laid plans is an acknowledgement that something has just got fucked up for no apparent reason, or because something inevitable (government, parents, teenage kid, fate, whatever) has acted against it.