Thirteen
During the 13
^{th} qepHom Saarbrücken in
2014, a new
idiomatic expression was revealed. It is based on the number thirteen
wa'maH wej and means something like "it is complicated".
One can use it in situations like:

qatlh QeH? Why is he angry?

wa'maH wej. That's complicated.
Origin
The origin of this expression is based on the ternary counting system explained in
The Klingon Dictionary, saying that Klingons used to count in pairs of 3. So 4 was actually said "3 plus 1", 6 was "3 plus 3". The higher the numbers get, the more complicated this system becomes. To say 12, you have "3 times 3 plus 3"  and then: it becomes complicated. That's where the expression came from.
See also