psychological warfare during interview
Do you deliberately give a solution that's suboptimal (though better than brute force) even though you have memorized a more optimal one, to avoid raising expectations in the mind of the interviewer in terms of future questions he may throw at you. Assuming the suboptimal solution is already quite decent and you understood very well.
Example, recover binary search tree, which is leetcode number 99. The "straight forward" solution has space of o(n), while a solution using Morris traversal has o(1) space, same time complexity.