What made Islam so appealing to people in the first hundred years following its development?
Islam began as a military movement. Its subjects paid higher taxes than its converts which caused a number of people to convert. The military life, accompanied by first choice of the available women and up to four wives, appealed to a number of young men. The women had no choice. That concept brought about many conversions and left fewer wives available for the remaining population.
If the opposite sex hits on you, or looks like they're about to, then you're appealing. Some might ask themselves "Well, aren't most people too shy to approach someone they find attractive?" No, that's why the word "appealing" is used. If you're appealing, that means that you're not just attractive, but more importantly, you're approachable. There's no point in being "hot" if you have a threatening presence (ie, if you're a bitch).
The development of farming enabled early people to form permanent settlements. Previously, hunter-gatherers had to move around, following game and searching for seasonal vegetation to eat. Crops required people to remain in a fixed location. Farming also enabled people to provide for winter sustenance, since grain can be stored until the next harvest.
The features of ice cream that most people find appealing is the fact that it is creamy, sweet, and cold. That combination is something that most people (and some animals) find physically appealing in many foods. Pudding has the creamy and sweet features. Other frozen treats are sweet and cold. But ice cream has it all.
The incentive and reward based approach to motivation emphasize the appealing properties of external objects or goals. Major chunk of the people are driven by these two needs according to Maslow's theory. People work only when they feel that they will be rewarded for the work they have done/will be doing. If an additional incentive or promotion is shown people get motivated to achieve the goal.