The Westminster Confession of Faith (16.7) is quite helpful in summarizing why works that are externally good are not pleasing in the sight of the Lord:
Works done by unregenerate men,
although for the matter of them they may be things which God commands,
and of good use both to themselves and others;
 they proceed not from a heart purified by faith;
 nor are done in a right manner, according to the Word;
 nor to a right end, the glory of God;
they are therefore sinful and can not please God, or make a man meet to receive grace from God.
And yet their neglect of them is more sinful, and displeasing unto God.
In other words, having the right motive, the right standard, and the right goal are the three necessary and sufficient conditions for good works according to the Bible.
I appreciate in particular that this summary takes seriously the biblical themes that “without faith it is impossible to please [God]” (Heb. 11:6) and that “whatever does not proceed from faith is sin” (Rom. 14:23) and that faith working through love—for God and for our neighbor—is essential (1 Corinthians 13; Luke 10:27; Gal. 5:6, etc.) and that all things are to be done for God’s glory in accordance with his revealed will (1 Cor. 10:31).
This triad is also helpful for thinking about what it means to do everyday activities in a Christian way. For example, John Frame writes:
In everything we do, we seek to obey God’s commands. There are, of course, human activities for which there are no explicit biblical prescriptions. Scripture doesn’t tell us how to change a tire, for instance. But there are biblical commands that are relevant to tire changing, as to everything else.
In all activities, we are to glorify God (1 Cor. 10:31).
In everything we are to be motivated by faith (Rom. 14:23) and love (1 Cor. 13:1-3).
In everything, we are to act in the name of the Lord Jesus (Col. 3:17), with all our heart (3:23). When I change a tire, I should do it to the glory of God.
The details I need to work out myself, but always in the framework of God’s broad commands concerning my motives and goals.