"And when the people complained, it displeased the Lord: and the Lord heard it; and His anger was kindled; and the fire of the Lord burnt among them, and consumed them that were in the uttermost parts of the camp" (Numbers 11:1).
The Lord is not pleased when we complain about our circumstances, no matter how grievous they may seem to us. Our example is Christ, always. "For even hereunto were ye called: because Christ also suffered for us, leaving us an example, that ye should follow His steps" (I Peter 2:21).
The children of Israel complained once too much. Forgetting all of God's blessings in miraculously freeing them from slavery and providing all their needs, they repeatedly complained about their lot, one thing after another. "But with many of them God was not well pleased: for they were overthrown in the wilderness. Now these things were our examples, to the intent that we should not lust after evil things, as they also lusted. . . . Neither murmur ye, as some of them also murmured, and were destroyed of the destroyer" (I Corinthians 10:5-6,10).
God may not deal with a complaining Christian as severely as He did with His chosen people Israel, but we can be sure He is displeased when we, who have received the blessing of eternal salvation by His gracious gift through Christ, forget His benefits and complain about His testings. "Do all things without mumurings and disputings" He has commanded (Philippians 2:14) -- that is, without complaining and arguing about our treatment.
We can be confident that He is allowing these difficulties for some good purpose in preparing us for our service for Him in eternity. We should not forget what happened to the complainers in ancient Israel. "Now all these things happened unto them for ensamples: and they are written for our admonition" (I Corinthians 10:11). HMM