Thanks to the big screen in the Frankfurt underground for this:

Der Utopist sieht das Paradies, der Realist das Paradies plus Schlange

— Friedrich Hebbel

Or in translation:

The utopian sees Paradise; the realist sees Paradise plus a queue serpent

UPDATE: Many, many thanks to Stefan in the comments for pointing out my inaccuracy and lack of cultural knowledge. I assumed it was about having to queue up outside heaven, but it seems it's actually about a serpent (a reference to Eden, I guess?). I have to say, I prefer my version…