A while back I read a Cracked article that pointed out that Bushido is actually a modern concept, and was just used to subjugate the Japanese populace into doing what the Japanese Empire wanted.
However, considering that this is from a Cracked article, I'm not entirely satisfied with everything they present, especially the article's comparison to a football player. It's been bothering me for quite some time, and I'm hoping that /r/AskHistorians can provide me with a more professional response than any other place on the internet.
So, what were samurai really like? Were they selfish or honorable? What were their customs? Were they really just hired men? Did they follow a set of morals and strict traditions? I've heard that their morning routine involved contemplating death: what did they do with their mornings? How common was hara-kiri? Is the popular image of samurai today similar at all to what they were really like? What exactly was Bushido, or whatever it was back in feudal Japan? What did it entail?
Furthermore, if you have the time: How comparable exactly were Media val European Knights and Feudal Japanese Samurai? What are some of the greatest exploits and feats that samurai have accomplished or done in history? What are some of the most famous samurai?
I'm sorry if I'm shooting off too many questions, but I'm really genuinly curious about this subject.
Bonus: I saw the film "13 Assassins". Is it just made up, or is there some historical accuracy at all to it?
I would say the cracked article is more or less correct, although I might take issue with the last paragraph, where it implies that the creation of Bushidō was a willful strategy. The reading that I've done suggests that the invention of a warrior ethic and its subsequent appropriation by state militarism was more complex and contingent, rather than being directed by some mastermind of social engineering.
If you want a pretty good overview of the creation of Bushidō, as well as what kind of historical roots it drew on, see Hurst, "Death, Honor, Loyalty: The Bushidō Ideal (need Jstor access)
Benesch, Bushidō: The Creation of a Martial Ethic in Late Meiji Japan (Dissertation PDF, freely available online)
It is also important to remember that many of the rules for samurai that the ideals of Bushidō were based on were written in the peaceful Tokugawa era (Hagakure is probably the most famous example). At the start of the Tokugawa shogunate, social classes became completely hereditary, and although the samurai were still warriors in name, their actual jobs were in administration, tax collection, and the like. In other words, at the very same moment that samurai became a well defined class, they ceased to function as warriors. The most famous of the historical references for Bushidō were thus written by a bunch of bureaucrats who had never seen battle, nostalgic for the days of their grandfathers.
As far as samurai before the Tokugawa are concerned, probably the best advice I can give you is to say that samurai, like all people, were somewhat of a mixed bag. There were loyal samurai as well as treacherous samurai, at certain points in their history, they may well have been nothing more than hired swords, at others they were a hereditary class. The heyday of fighting in the Sengoku era that came before the Tokugawa was also the low point for any coherent vision of the samurai, as the social upheaval allowed for pretty much anyone with a sword to be a "samurai" if they wanted. Toyotomi Hideyoshi, the second unifier of Japan, was not born into a samurai family, for example.
I can't answer your other questions - my specialty is post-Meiji restoration, and I just don't know the level of detail about daily life that you're asking about for earlier eras.
If you want more information on samurai, Karl Friday really is the formost expert writing in English. The only controversy I know surrounding his work is a disagreement between his book, Hired Swords: The Rise of Private Warrior Power in Early Japan and William Wayne Farris's Heavenly Warriors: The Evolution of Japan's Military, 500-1300 about the origins of the samurai and how exactly warriors rose to power.
I didn't see 13 Assassins. I cannot comment on it.
If you want to get a sense of what the early samurai were like, I would suggest reading the Tale of Heike. That book should give you a sense of what the samurai were like at the end of the Heian period and early Kamakura period (ca1200). There are many translations in English so it shouldn't be hard to find. When you read this you see that the early samurai already had a sense of tradition as warriors. They were highly individualistic and really were feudal in the sense that they gave loyalty and service to men who protected them and rewarded them with land. (This of course meant that they would betray their lord if the lord could not protect them.)
The Taiheiki at the end of the Kamakura period and beginning of Muromachi period (ca1300) should give you a sense of the political intrigue, battles, and the rise of infantry warfare.
Once you get to the Warring States period (1477-1603) there are many books on samurai lords (Oda Nobunaga, Toyotomi Hideyoshi, Tokugawa Ieyasu) and individual warriors (Miyamoto Musashi) so there's plenty of information.
In the Edo period (1603-1868), there's even more information in English. And as tokumei notes, the samurai code began to be written down in this period. Perhaps the most famous is Hagakure, but you can also get The Code of the Samurai by Taira Shigekuni. If you want to read about the life of ordinary samurai, you can read Musui's Story an autobiography of Katsu Musui (Kokichi).
Eiko Ikegami's The Taming of the Samurai addresses the changes in samurai culture over this time period.
Key difference between European knights and Japanese samurai I would say is the existence of Courtly Love. You don't have that in the samurai, and instead you find Shudo (male-male love) practiced by many (not all) samurai. Aside from that the two groups are remarkably similar.