For some reason, I keep thinking of the analogy of having a baby when I this PhD thing.
If you think about it, the process is very similar, especially in the later years.
Year 3 = first trimester. You feel like you’re on top of the world (= like you just had sex). You have no responsibilities and face little or no expectations.
Year 4 = second trimester. The morning sickness/mood swings start. Periodically, you still remember why you’re doing this. Other times, you want to abort the whole thing.
Year 5 = third trimester. Life becomes difficult. Labor starts, and you’re in a lot of pain. You worry about whether your "baby” will have all its fingers and toes intact ( = whether you’ll realize there’s a defect in your code which invalidates all your findings).
Year 6…If you’re still in grad school by year 6, they’ll induce labor by cutting your funding.