The Worst Feeling - As a jungler is when every lane loses while you're making quality ganks.
It happens. No reason to complain. But it honestly feels like trash when every single lane loses.
The only thing worse is when you camp someones lane but they're soooo behind in levels and items from dying so much, that you camping their lane actually wastes your time and nothing good comes out
if I'm ahead, they have a mixed comp, and the support buys 
sejuani doesn't need the extra slow
if I'm aiming for mid game and
(before cinderhulk) If I'm aiming for late game.
+
+
then
and then finish my belt into
is a total waste. If you need an extra slow (some games you really need it) then get
is also quite useful on sejuani since she burns considerable mana thanks to her Q costing her the same as her ult... you generally get 20% CDR with pretty much any build you go (sometimes even more) so that Q is on pretty short CD so spamming it burns a lot of mana.