Because the Crusades are such a broad swath of history, I think you would need to break it down further to get the best answer. The first crusade really was dominated by religious fervor. There was a shared desire to reclaim Jerusalem. Most of the first crusaders came from France, but the concept of "France" needs to be loosely applied here. The dominant factions were the men from Flanders (Godfrey of Bouillon, Baldwin of Boulogne, Stephen of Blois), men from southern France (Raymond of Toulouse), and men from Norman controlled Italy (Bohemond of Taranto, Tancred of Hauteville). These Crusaders remained remarkably cohesive as they took the land route to Constantinople. The first cracks in their unity began with making a pledge of fealty to Emperor Alexios of Byzantium. One of the stipulations of their pledge to the Emperor was to return any lands that were once part of the Byzantine Empire back to the Byzantines. This became an issue after the Crusaders took Edessa, but more notably when they fought a bloody siege to take Antioch. I don't want to get bogged down in the details, but it was a crazy siege, and at one point seemed so hopeless that Stephen of Blois actually went back to France (and was branded a coward). However, the Crusaders took and held the city. At this point, Bohemond did not want to hand over the city and surrounding territory to Alexios. Bohemond remained and established the Principality of Antioch, both betraying his pledge to Alexios (although he would argue that Alexios abandoned the Crusaders by not aiding the siege at Antioch), and no longer carrying on the fight to Jerusalem. This move is heavily debated as to whether or not he was making a calculated land grab all along, and how seriously he took his vows to retake the holy land. A similar battle would take place as the Crusaders took Jerusalem. It became apparent that the first men over the walls would probably become King, so the various contingents vied to capture their share of the spoils. This led to some interesting tactical arrangements during the final siege, but probably did not adversely affect their ability to fight.

The Third Crusade was notable in that both the Angevin King Richard the Lionheart and French King Phillip II Augustus went along together (as well as the Holy Roman Emperor Frederick Barbarossa). The logistics of two rival Kings going to the holy land proved incredibly difficult. They signed a series of pledges/truces to essentially guarantee that they would both go to the Holy Land at the same time, spend three years there together, and not attack each other's kingdoms back home during this time span. They actually initially stuck to this plan, but the crusading armies showed cracks during the siege of Acre. Acre was a human meat grinder and lasted for almost two years. Eventually the crusaders overcame the defenses. Various factions staked their claims in the city, but a divide arose between Richard and Phillip. This was as far as Phillip would go in the Crusade. He was ill, and had domestic issues within his kingdom, so he sailed home. He left his army in the Holy Land though. This essentially left Richard as the leader of the Third Crusade. It's at this point where we see the differing views of the Crusaders come into play. Richard wanted to drive into Egypt and cut off the Muslim financing and supply of their war effort. Much of his army however refused to march past Jerusalem and not take it. A rift developed and the crusading army was not strong enough, when factionalized, to take either Egypt or Jerusalem.

The last best example is the Fourth Crusade. Keep in mind that the Fourth Crusade was supposed to deliver 30,000 men to Egypt, but delivered less than half of this number to Constantinople, sacking it and forming a new Latin Empire of Constantinople. To best understand what happened, it began with French knights contracting the Venetians to build a huge fleet to transfer men and horses to the Holy Land. Venice suspended trading activity completely and recruited basically every man in the lagoon to help prepare. They demanded a relatively fair but still outrageous price for this effort. They delivered, but the French knights did not. Many of the crusaders did not want to launch out of Venice, so they chose other, more convenient ports. The knights who did show up to venice were stuck with a huge debt. The Venetians held them hostage on an island in the lagoon until they paid everything they could, and when they could not cover the whole of their debts, the 90 year old, blind Doge of Venice essentially used them to advance his own agenda. The crusading army ravaged the Dalmatian coast, settling scores with old rivals. The crusading army sacked a Christian city (Zara). The entire crusade was excommunicated at various points for their evil deeds, although the leading nobles outright ignored papal communications throughout much of the struggle. The Doge eventually steered the crusading army to Constantinople, and forced the army to take the city to pay back its debts to Venice. While it's amazing that they actually overcame the city's defenses, the crusade was a smashing success for Venice, who risked their entire livelihood on the venture. However the crusading army was led hopelessly astray. Christians seeking salvation laid siege to Christian cities, slaughtered Christians, committed atrocities, robbed the Hagia Sophia, etc. These actions all sprang from mismanagement by the leaders of the Crusade.

These are rough overviews but I think they demonstrate some of what you're asking, at least from a bird's eye view.