Wisdom from the Early Stoics, Zeno of Citium 5

Zeno himself was sour and of a frowning countenance. He was very niggardly too, clinging to meanness unworthy of a Greek, on the plea of economy.

If he pitched into anyone he would do it concisely, and not effusively, keeping him rather at arm's length. I mean, for example, his remark upon the fop showing himself off. When he was slowly picking his way across a watercourse, "With good reason," said Zeno, "he looks askance at the mud, for he can't see his face in it." 

When a certain Cynic declared he had no oil in his flask and begged some of him, Zeno refused to give him any. However, as the man went away, Zeno bade him consider which of the two was the more impudent. 

Being enamored of Chremonides, as he and Cleanthes were sitting beside the youth, he got up, and upon Cleanthes expressing surprise, "Good physicians tell us," said he, "that the best cure for inflammation is repose." 

When of two reclining next to each other over the wine, the one who was neighbor to Zeno kicked the guest below him, Zeno himself nudged the man with his knee, and upon the man turning round, inquired, "How do you think your neighbor liked what you did to him?"

To a lover of boys he remarked, "Just as schoolmasters lose their common-sense by spending all their time with boys, so it is with people like you." 

He used to say that the very exact expressions used by those who avoided solecisms were like the coins struck by Alexander: they were beautiful in appearance and well-rounded like the coins, but none the better on that account. 

Words of the opposite kind he would compare to the Attic tetradrachms, which, though struck carelessly and inartistically, nevertheless outweighed the ornate phrases. 

When his pupil Ariston discoursed at length in an uninspired manner, sometimes in a headstrong and over-confident way, "Your father," said he, "must have been drunk when he begat you." Hence he would call him a chatterbox, being himself concise in speech. 

—Diogenes Laërtius, 7.16-18