“made me angry.” The NET text note on Deuteronomy 4:25 gets the sense of the text correctly when it says, “The infinitive construct [in the Hebrew text] is understood here as indicating the result, not the intention of their actions.” Although many English versions use the word “provoke,” the Israelites did not worship idols with the intention of provoking God. But the result of their idolatry was that God was angered. In everyday English, “provoke” means to do something to intentionally upset someone, and that is not what was happening with Israel’s idolatry.
“a foolish nation.” That is, a nation that does not recognize God, the creator of the heavens and the earth, and is therefore foolish.