That's the difference between irony and sarcasm. Irony can be spontaneous, while sarcasm requires volition. You have to create sarcasm.
I've won Satan's lottery.
Blessed are the dumbfucks.
How could you deal with a creature as devious as woman.
No one knows why, but second only to eating the brains of the living, the dead love affordable prefab furniture.
Even a mentally challenged shark would figure out that sea turtles did not wear boxer shorts printed in flying piggies, and no sea turtle would be yattering streams of obscenities between chain-smoker gasps of breath.