Some of us, upon coming to faith, develop a feeling that there must be some other place - a special, better place - where God wants us to go. We feel so privileged to be rescued from our sin, we desire to do big things for Him. We think, "Certainly God doesn't want me to continue on at the same job, or live in the same neighborhood, or associate with the same people as before!" We want to make a clean break from our old lives and head off towards a more noble destiny.
But in our verse today, Paul tells us to remain in that condition in which we were called. This comes partway through a chapter where he's addressing single people, married people, slaves, free men, Greeks, and Jews. Paul tells us that if a single person can remain single, they can devote more time and energy to God's work. And that a married person should stay married in the hopes that they might win over their unsaved spouse. Slaves can minister to their masters, and Greeks don't have to become more Jewish to live a life fully pleasing to God.
Instead of looking at your situation as something that must be left behind, why not look at it as the mission field where God has called you? Whether you're a waiter, a computer programmer, a truck driver, a lawyer... you are uniquely suited to reach the other people in those places. Do you live in "sin city"? Be a light that shines brighter than the neon. Are you married to someone who hates Christians? Then by staying with such a person you demonstrate the patient faithfulness God showed when He waited on you to turn to Him.
Of course, you might genuinely be in a situation where there's no way to please God. Someone involved with dealing drugs or in the adult entertainment industry will be unable to continue on in such pursuits. (Although great testimony has often been demonstrated by those who gave up much for the sake of Christ!) But most of us, even when surrounded by wickedness, can still find a way to bring Christ's light into those dark places, maintaining our integrity along the way. And God, by His providence, has got you exactly where He wants you.