Waiting eagerly for milestones to happen or for difficult phases to end means wishing away precious time. The speaker advises against constantly looking forward to the next thing at the expense of the present, stressing the importance of cherishing the current moment. They emphasize that everything, both good and bad, passes by swiftly, urging to make the most out of the present instead of constantly waiting for the future. The speaker recommends holding onto the rule of never wishing for less time, especially with children, as time with loved ones is limited and fleeting.