Here are a few, all by Johann Wolfgang von Goethe :
* Consolation when enduring student poverty:
"Everything in the world may be endured except continued prosperity."
* A good motto for us all?
"Nothing is worse than active ignorance."
* The importance of having a bit of fun (though I'm not sure about the 'reasonable words'):
"One ought, every day at least, to hear a little song, read a good poem, see a fine picture, and if it were possible, to speak a few reasonable words."
* When writing up:
"When ideas fail, words come in very handy."
* And here is my favourite (I'm trying to bear this in mind as I start my literature review...):
"Whatever you can do or dream, begin it. Boldness has genius, power and magic in it."