My mistake bro. You're right. The rest of training was very complex and not everyone passes. Indoc is the easy part.
It's been three years since I went through it, but I'd say it all comes down to study habits. Of all the guys I saw get together in study groups at the end of the, virtually none of them flunked systems. Systems isn't "hard" in terms of the concepts, the difficulty lies in the pace of the class. If you're in any part 121 groundschool, you NEED to be proactive with your training. If you don't understand something, ASK! The instructor is not gonna think you're a moron. The overall process is like college........it all comes down to your personal schedule and study habits. If you blow it off until the night before the written, chances are not in your favor. And yes, you need to party/get out of town/go to a ballgame/whatever occasionally, just make sure you do your leisure stuff in moderation.
As for the sim, people say it's not for "real" pilots (whatever) but buying one of those $40 true-to-life packages of the aircraft you'll be training on for Microsoft Flight Simulator does help A LOT. It does. Especially for those with no previous high-performance/turbine experience. The sim is all about speed management (knowning when to slow/configure -- getting high/fast/unstabilized is pretty common early on) and knowing your callouts and flows (sort of like memorizing lines to a play). Situational awareness is also big, but unfortunately that usually only comes with experience. I didn't start to really feel that I was developing that until my second recurrent. Key is, know your callouts/flows/limitations cold. The rest is just flying a big twin.
As for Indoc (I should have started with this) -- it is a great opportunity to catch up on your drinking. Some interesting stuff is in there (the sexual harrasment videos are hysterical) like how to read a release, company weather policy (i.e. requirements for an alternate/second alternate, maximum winds, i dunno), but most of it is very sedating. On the line you just need a working knowledge of this stuff, and if you ever need the information, you need to know where to look it up in your manual. It's easy just kinda boring overall.
P.S. Siucavflight, that avatar of yours just makes my day.
Uh, yeah I wanna bang Siucavflight's avatar.