Side effect: you have a vision of the first move they'd make after taking your mom/dad on a date

First commentor missed the Cassandra side effect: you can do nothing to change it and no one believes you.

You can see a person's next move at the expense of generating negative causality, wherein large objects are attracted to you at high speed. See the man unwrapping a sandwich? Boom, hit by a bus/piano/anvil/whale.

Side effect: you're never prepared for the move they will be making next.