European exploration was caused by the desire to get resources from Asia, such as silk, gold, spices and other valuble items for trade The reason the Europeans wanted to these resources from Asia was because it could be brought back to Europe and sold on with huge profit.
Another cause to exploration was finding new water routes to new locations. The Europeans wanted to find new water routes to Asia because the crusades had ended.
One of the most devastating effects of exploration was the spread of foreign diseases, one of them being the Bubonic plague also known as the Black death, which killed about 50,000,000 people or about 60% of Europe's population.
Being that you had to carry items to trade on your ship, others would want to get those items for a low cost..., this was the age of pirates! why trade something when you could get it for free, this is what the pirates did, they raided other ships, took hostages and raped them... Shiver me timbers!