I have had and currently have clients who are so, so serious about working on themselves.
"What should I work on next?" They ask, as if full-time work will get them there faster. I often recommend having fun, hiking in the forest, watching a comic film, laughing even if its forced at first or just lazing about dreaming.
In the words of John Lennon: "Life happens while you're busy making other plans." Vacations from constant mindfulness or small breaks for fun allows the sub-conscious flow within us to recreate ourselves in different ways and allow integration to occur - if you need an explanation.