Nothing is fool-proof to a sufficiently talented fool.
Why do we remember the past, but not the future?
What lies north of the North Pole?
So remember to look up at the stars and not down at your feet. Try to make sense of what you see and hold on to that childlike wonder about what makes the universe exist.
If time travel is possible, where are the tourists from the future?
It is no good getting furious if you get stuck. What I do is keep thinking about the problem but work on something else. Sometimes it is years before I see the way forward. In the case of information loss and black holes, it was 29 years.