Are you desiring that which you left behind?
And the mixt multitude that was among them fell a lusting: and the children of Israel also wept again, and said, Who shall give us flesh to eat? We remember the fish, which we did eat in Egypt freely; the cucumbers, and the melons, and the leeks, and the onions, and the garlick: But now our soul is dried away: there is nothing at all, beside this manna, before our eyes. (Numbers 11:4-6 KJV)
The Israelites were looking behind rather than ahead; choosing to view what they gave up rather than all they had gained along their journey from Egypt to the Promised Land. They desired to have the finest meats and delicacies as those which were available to consume in Egypt. Their wanted to fill their bellies with choicest of meats, fresh fish, and finest vegetable rather than the simple manna which God had provided. Instead of being thankful for His provision, which met all their needs perfectly, they began a chorus of whining and complaining to God desiring the best of this world rather than that of an eternal value.
How often do you and I do this? God has graciously provided just we needed time and time again as we need it and we choose to place our focus upon many worldly things we desire, or were led to give up for our spiritual good, rather than giving honor and glory to God for His wondrous provision. God knows exactly what we need in this world of an eternal value and to complain and whine about what we are missing out on is certainly taking the mercy and grace of God for granted; forgetting if God gave us exactly what we deserve all would face a death sentence for their sin rather than feasting on His great mercy and grace.