In the beginning, Native American tribes were accommodating and definitely benefited from European colonization, and vice versa. The Native Americans were introduced to new weapons and industrial tools while the Europeans learned about agriculture and different foods that were unknown to them such as corn, potatoes, pumpkin, yams, and lima beans. The Native Americans used different tactics to lure and hunt animals, while European agriculture was based on grain and wheat and rye and relied on domesticated animals and machinery to feed the population, horses and guns were used to hunt.
The French in particular, who were interested in fur and trade, as well as silk (which was highly sought after) would waste resources by skinning the animals and leaving the rest of the meat to rot. The Spanish on the other hand were after gold and land amongst other things. While some settlers were not hostile towards the Native Americans, many were. Communication was difficult as tribes across America had their own language and the culture was purely based on speaking, not writing.
One of the major downsides was that with these new settlers also came foreign diseases that these tribes were not immune to, such as smallpox and the plague, which wiped out many people by the thousands as there was no known cure.
As time went on, and the Natives realized the English were not planning to leave, but began expanding, relations between the two were tense. In the end the broken treaties and deals lead to mistrust and therefore many wars and battles -- Europeans were enforcing religious laws and selling land, essentially cheating the Native Americans out of their homes and culture, and most importantly their lifestyle. They were forced into reservations and their freedom was taken away, primarily being enslaved into harsh labor.