The superficially cordial relations may have been the rule, but there were exceptions. The first Arab attack on a Jewish settlement occurred in 1886 when hundreds of Arabs descended on Petah Tikva in an attempt to destroy it. Around 1898 the Ottoman Empire outlawed Jewish ownership of land in Palestine but it reversed itself under European pressure in 1901. Arabs attacked Jews in Tiberias in 1901 and 1904, and in 1911 Arabs strongly protested the legal Jewish purchase of a large tract of land from the Sursuq absentee landlords of Beirut (the al-Fula incident.)
All of these incidents had one thing in common: Arabs protesting Jewish ownership of land in Palestine. No matter how legally the land was acquired, the very idea of Jews in control of land has historically caused reflexive Arab protest. Even in this early time period the Arab leaders would try to find legal arguments against Jewish land ownership.
History is almost necessarily weighted towards documents, and when historians talk about "Arabs" in this context it appears to refer to the Arab intelligentsia - the leaders, the writers, and those who are most likely to leave a record of their thoughts. Ordinary Arabs who moved to Palestine to work did not leave such a historical record, and their opinions of the Jews are left up to conjecture. While anti-semitism is a given in the Arab world at large, by the end of World War I they were starting to work directly for Jews. Clearly their antipathy for Jews did not outweigh their practical desire for jobs. In fact, there is some evidence that the most pronounced anti-semitism in the early 1900s came from Arab Christians, not Muslims.
In short, the average Arab in Palestine in this timeframe was more interested in his economic well-being than with politics or hating Jews. But that didn't mean that they could not be easily used by the press and by self-proclaimed leaders. The lack of sophistication among the average Arab, along with his sense of communal unity and his pre-existing biases, made him uniquely susceptible to manipulation by others. The entire concept of the "Arab street" has been a myth perpetuated by Arab leaders to strike fear into Westerners, and there was never a shortage of Arabs who could be easily manipulated into rioting or other violence.
These "leaders" had their own agenda. Arab nationalism emerged from a number of factors - the planting of nationalistic ideas from American missionary/teachers in the Middle East, the the decline of the Ottoman empire and early hopes for a pan-Arab state that would result, exposure to Zionist ideas and fear of Zionist plans being realized. In large part, Palestinian Arab nationalism seems to have been fueled more by their disgust at the possibility of Jews controlling any "Arab" land rather than any real desire to build their own country. The well-being of the Arab people themselves was never a part of the equation.
The best proof of Palestinian Arab "leaders" who had no interest in their followers except as pawns comes from the life of the infamous Mohammad Amin al-Husayni, the Mufti of Jerusalem. At first, Husayni advocated independence for "Greater Syria" which comprised today's Syria, Jordan, Lebanon and Israel. In fact, he wrote for a Palestinian newspaper named "Suriyya al-Janubiyya", or "Southern Syria" in English. This is not surprising as from the Arab perspective, Palestine had historically been considered "southern Syria" - an Arab map from 952 CE shows Jerusalem as part of Syria and Palestine is not listed as one of the 17 Islamic nations at that time.
But after the Sykes-Picot agreement dividing the Middle East between Britain and France, Husayni's dream of pan-Arabism was modified to pure anti-semitism disguised as Palestinian Arab nationalism. He instigated riots (with British help ) against the Jews during Passover in 1920, killing 5 Jews as Arabs ransacked the Jewish Quarter of Jerusalem.
Husayni's role in the riots bought him a ten-year prison sentence in absentia (he fled to Syria to avoid jail,) but he was granted amnesty and the new British civil administration appointed him Mufti of Jerusalem in 1921. As such he built his power base, getting elected as leader of the Supreme Muslim Council, controllingWaqf funds, the shari'a courts and many jobs. As he cemented his leadership role, his concerns for his Palestinian Arab brethren diminished.
For their part, the Palestinian Arab masses were not happy about this pogrom. 82 Arab villages who claimed to represent 70% of the Palestinian population and 90% of the peasant landowners condemned the riots and said that they prefer a Jewish settlement under British mandate to being at the mercy of the Arab effendi and money-lenders. These were not Husayni's concerns.
Three weeks after he reassured the British High Commissioner that he was a peaceful man dedicated to tranquility, Husayni discreetly instigated another set of riots, these much deadlier, in Jaffa and later to a few other areas. 43 Jews were killed.
In the wake of these riots, the Haycraft Commission placed the blame almost entirely on Arabs, and noted that they were encouraged by their leaders. While the 1921 riots do not appear to have been pre-planned (they were sparked by an altercation between Bolshevik and Communist Jews during a May Day march) they were fanned by unfounded rumors of Jews killing Arabs, showing again how easily a spark can turn into a conflagration when you combine Arab ignorance, latent anti-semitism and naivete. Nevertheless, Haycraft even-handedly mentioned that Arab fears and antipathy towards Jewish immigration and Zionism was a cause of the rioting.
This motif, where Arab violence would be blamed partially on Jews, helped set the stage for British restrictions on Jewish land ownership and immigration in the decades to follow. Not surprisingly, leaders like Husayni would see that instigating Arab riots would bring immediate political results, and even threats of violence could be used as an effective political tool.