They take the advice literally (but rarely have the courage to follow it), and that's a misunderstanding.
Many people see some kind of logic between the first sentence of the quote and the second; there isn't. Sailing away from safe harbour will not change the fact that you'll do some things, not do some others, and regret the ones you've not done! The grass is always greener on the other side of the fence!
So is the quote completely misleading?
There is no lasting happiness from getting as many things as one can (there's always more to have), or from visiting as many places as one can (there's always more to see)... If 'dreaming' is wishing then — as wishing conditions seeking, which ultimately conditions suffering — 'dreaming' of things or experiences is simply not a path to lasting happiness. You know so: like all of us, you've personally tried that path of 'acquisition' before, you know it leads to 'never enough' rather than to lasting happiness.
'Just a bit more and it'll be perfect.' Things and views are never as perfect as hoped for, experiences never last as long as hoped for, good memories fade faster than hoped for, bad memories stick longer... Craving seems to never stop, the anguish of not having had the best possible experience seems to never stop...
Ignorance is the belief that there exists a way to get the world one wants (incl. a lack of older bad memories) and that getting it would at last lead to untainted, true, happiness. This is just a childish misconception (of the nature of desire, of the nature of satisfaction, of the nature of self, of the nature of all phenomena).
The quote is inspiring and true, but figuratively: sail away from the safe harbour of an illusory safety, built from imaging that impermanent things are permanent: wealth, health, relationships, environment, etc! Explore who you are, what stories you tell yourself about who you are, what expectations you have that spoil your experience, what representations you have that put a veil on reality and prevent you from seeing things as they are! Dream of the cessation of suffering. Discover dissatisfaction, impermanence, non-self! Understand them, understand your experience (of life and of yourself). Discover how ignorance ultimately leads to suffering (dependent origination). Realise Nirvāṇa now, you don't know when it'll be too late!