Wisdom from the Early Cynics, Diogenes 7

And one day when Plato had invited to his house friends coming from Dionysius, Diogenes trampled upon his carpets and said, "I trample upon Plato's vainglory." 

Plato's reply was, "How much pride you expose to view, Diogenes, by seeming not to be proud." 

Others tell us that what Diogenes said was, "I trample upon the pride of Plato," who retorted, "Yes, Diogenes, with pride of another sort."

Sotion, however, in his fourth book makes the Cynic address this remark to Plato himself. 

Diogenes once asked him for wine, and after that also for some dried figs; and Plato sent him a whole jar full. 

Then the other said, "If someone asks you how many two and two are, will you answer, twenty? So, it seems, you neither give as you are asked nor answer as you are questioned." 

Thus he scoffed at him as one who talked without end. 

—Diogenes Laërtius, 6.26