Moshe and Aharon bring upon Egypt the plague of the frogs. It gets to be so bad that Pharoah calls Moshe and orders him to beseech from Hashem that He stop the plague. Moshe asks when he would like the plague to be cancelled. In 8:6 Pharoah responds and says, "ויאמר למחר" - - And he says Tomorrow.
Pharoah had the oppotunity to say stop it right now and Moshe would have. Yet he chose to request Moshe only cancel the plague the next day. Why did he do this? Why did he want to suffer for another day with the frogs?
The various commentaries tell us that Pharoah suspected Moshe was possibly a magician. If he would say cancel it right now, Moshe would be able to. By saying canel it tomorrow, he is making it more difficult and maybe Moshe would not be able to and he would prove Moshe to be a fraud.
Look at how destructive and harmful גאוה, haughtiness, can be. Pharoah was willing to suffer with the horrid frogs for an extra day just on the chance that he might be able to prove Moshe to be a charlatan and not a messenger of Hashem.
And don't think the plague was not so bad, not such a big deal, that he could just put up with it for another day. It must have been pretty horrible. It already brought Pharoah to his knees and made him agree to Moshe's demands. For that to have happened, it must have been pretty bad.
Yet despite that, he is willing to suffer for another day...