I Wonder about Pitching Stats

There are a lot of statistics in baseball. Pitching stats especially confuse me. There seem to be a lot of rules so I'll just cover the most common scenarios. If you need more complete definitions, check out more comprehensive sites, like this one. Here are some that I found most relevant:

Different types of pitchers:

• Starter - A pitcher who starts games
• Bullpen / Relievers - The group of pitchers that enter the game at some point after the game has started
• Closer - A reliever who usually pitches the last inning in a save situation, or in an important game

Useful Definitions:

• Go-Ahead run - The run that gives the lead with which the game is won
• Decision - a win or a loss
  

Different stats a pitcher can be credited with for a game:

• Win - credited to the pitcher on the winning team who was pitching when his team first took the ultimate lead. If this was a starting pitcher, he must have completed at least 5 innings. There must be a winning pitcher.
  
• Loss - credited to the pitcher who was responsible for the go-ahead run on the opposing team. I'm pretty sure that in the case of pitching changes mid-inning, a pitcher is responsible for any batter that got on base while he was pitching. Any pitcher who enters the game with his team tied or ahead can be credited with a loss, no matter how many innings he plays. There must be a losing pitcher.
• No-Decision - A pitcher who starts the game but it not credited with a win or a loss is considered 'no decision'
• Save - credited to a pitcher who enters the game while his team is ahead, he finishes the game, his team ends with a win, and at least one of the following is true: his team was ahead by 3 runs or fewer, he pitched 3 or more innings, or the tying run was on base, at bat, or on deck. A pitcher cannot be credited with a save and a win in the same game. There is not always a save credited during a game.

It all seems very complicated to me! I think it's partly the inherent interdependencies of the game.