So many to choose from.
Time travel circuits disabled by Time Lords, however.
It does less and less, until it basically does nothing.
You can start early, but be aware that the user might change their mind.
Look for the explorer browser helpers.
Send in the clones.
Even if the typo is what confused you.
Over-engineering the solution.
Predicting the future.
Because pressing Volume-Up 100 times would be really annoying.