I enjoy making really vague predictions about the future to have an unearned celebration when the prediction inevitably is correct.
What do you gain from these prophecies?
It makes me feel wise and revered.
Trying to make vague enough predictions so that they come true is annoying and rude. You should do your best to try and make predictions that you think will hold weight.
Why do you care, it's just silly fun.
Some people might start to see your predictions as superfluous ramblings and won't take notice of your predictions if you are wrong too many times. Try giving a disclaimer that you are only doing it for fun and not to take it seriously.