I think all people, whether they want to or not, perform the will of God. Whether or not their will is God's will is another matter entirely. I'm not saying God's will is easy. It's best and for our good. To go your own way, even with good intentions and perhaps more pleasure, is still not best. All Christians should have a good idea what God wants for them. If they don't, then they've not been talking with God. For to prefer your own way in spite of knowing God is really to not know God and distance yourself from Him. If you like somebody, it makes sense you take time with them and listen to what they have to say. Doubting God is the direct result of not knowing God.
Everything God wills for a person cannot be known obviously, but I think he sets up signs (even if we don't understand them at first) to keep us on the straight and narrow. Now the thing is, you can convince yourself you're on the right path in Life quite easily. You can even make up signs. Especially if you have an overly logical bent. You know, or feel, uneasy and somewhat confused because you're trying to swim against the flow of the Holy Spirit. You have doubt. Not always in abundance, but if you have this persistent gnawing in your innermost being saying, "This isn't quite right," you should stop and listen to the Holy Spirit for guidance. Bungling ahead isn't good and should you continue rambling ahead, doing what you shouldn't do (or are supposed to do) you're wasting you're time and will experience a great deal of frustration and heartache. Going you're own way may even be easier for a time, but eventually at the end of your days, you'll find out how meaningless it all was.
What you do in Life should be meaningful and productive. A man can spend years doing something important with good intentions, yet still be at odds with the maker of Life.
Doing what you're designed to do isn't necessarily the most pleasurable thing in the world, but it will definately be the most fulfilling. You can think of it as building a city. Each person has their own job to do. To do somebody else's job is to hurt the city as a whole. Not doing your assigned task impedes progress and slows production. Everything is just a little less efficient than it could be.