(First of all, before I get into anything serious, let's put our h's in the right spot. It's catholic not chatolic. Sorry. Not a biggie, but I am a high school teacher after all.)
The reason Protestants do not confess to a priest goes back to two concepts. First of all, in ancient times, the followers of God were separated from God by sin. The priests were the only ones allowed to come before God (not to say that God didn't know or didn't care about what happened to the little guy when the priest wasn't acting on his behalf). Secondly and very importantly, when Jesus was crucified and He gave up His soul, the curtain in the temple separating the Holy of Holies from the rest of the temple was split in two. This curtain was thick and an earthquake (specifically the one that happened at Jesus's death) would not have resulted in its separation. This is the foundation for Protestants believing that we no longer have to use a priest as an intermediary between us and God. We (because I am one) take this as a sign that that which was separating us and God has been removed (namely sin, which is now covered and forgiven by the blood of the Christ).
Instead of going to a priest to confess, Protestants are to confess their sins directly to God. Also, confessing our sins to each other (put not necessarily to our priest or pastor or reverend or whatever your brand of Protestantism calls him) is a way that we stay accountable to keep from committing that sin.
As to the matter of the Trinity, most branches of Protestantism believe in the Trinity. Why only most? That is because the concept of the trinity is never explicitly stated in the Bible. It is something that has been gleaned from study and handed down for generations. The early church fathers that were involved in putting the Bible together were also responsible for much of our current extra-Biblical theology. Thus, most branches of Protestantism believe in the Trinity, but there are some that say the early fathers overstepped their bounds and that the concept of the Trinity is heresy. I would be, however, greatly surprised if even one person on this site who believed in Christianity held that there was no Trinity as, again, most Christians (and when I say Christians, I mean all of Christianity which includes Protestants and Catholics) believe in the Trinity.
As to the behavior of Catholics, there is, more or less, an impression among the more religious Protestants that Catholics are really only Christian in name. Don't get me wrong, I'm not saying I agree, I'm just saying that the impression is there. I also have a theory as to why that is. Here goes. Catholicism is older in the sense that it has continued for centuries as the body from which the other branches split. Like any group, the sad truth is that every group can survive on just ideals for only a short while. Eventually, every group that lasts must organize and that include creating customs, rituals, hierarchy, and other such things in order to make sure that the original ideals are being taught and upheld. Being older, Catholicism has had more time to create and perpetuate such rituals (which are not necessarily bad but can distract from the true purpose over time [give Protestantism another century or so and you'll probably see it just as clearly]). These rituals give some the impression that if they follow the motions, then they are Catholics and as such they call themselves Catholic. The truth is they have missed the true purpose of the rituals and of coming together as a body of believers. Unfortunately, as seems to usually be the case, we usually see the bad sides of a group before we see the good sides. And thus, a bad impression of the Catholicism is created. It would be fair to add that Protestantism has its fair share of hypocrites as well. The thing is, though, that given Protestantism's lack of standardized rituals, it is harder to see some of the hypocrites. (Food for thought: There is no such thing as a nominal, or non-practicing, Christian, Protestant, or Catholic. That's like me saying I'm a supporter of PETA but then going hunting and eating a cheeseburger afterwards. I may say I'm a supporter, but my actions will speak louder than my words.)
As to the split, yes, Martin Luther was the cause of the split, though, he was trying to reform the church, not split it apart. Also, he wrote 95 theses (plural of thesis) and nailed them to the door of the church. The theses highlight, as Angel said, areas where the church was no longer following the teachings of the Bible.
One thing Angel, I'm not sure exactly what you meant, but Protestants and Catholics both follow what is said in the Bible. The major difference is that Catholicism sees the Bible through lenses tinted with rituals and customs but also tinted with tradition and teachings from the early fathers of the church. Protestantism breaks away from the rituals in order, one, to not be distracted by them (though we are starting to build our own) and, two, to gain a deeper understanding of God by going back to source from which the rituals were created.
One last thought to leave you all with: Many people seem to think that Protestants are Christians and Catholics are Catholics. We are all Christians. Catholicism and Protestantism are both branches from the same tree. However, there are some things in our tree that claim to be branches but are actually just tricycles that got blow in during the last tornado. But don't worry, eventually someone will take them down (I mean that in the metaphorical sense).
About the length, gomen.