Mormonism, like so many other religions out there, puts a lot of emphasis on how we desperately need to control our thoughts. That's typically manifest through expressions like "guard your thoughts" and "keep your thoughts clean". This is because Satan, the fallen Star of the Morning, Lucifer the Great, the Devil himself, is always out there looking to temp and corrupt you. It's a horrifying idea that keeps a lot of us constantly on edge. Even now Satan and his minions are almost definitely chiseling away at your brain case in an attempt to infiltrate your every thought and desire. No one wants to lose his or her mind and will to the Enemy of All Righteousness, so we question our thoughts constantly, doubt our logic, second guess our impulses, and think twice before acting all because it might be coming from the wrong source.
In addition to putting up serious defense mechanisms against the Bad, Mormons are instructed to yield to the Light of Christ (our conscience) and learn to "open up to the Spirit", a.k.a. "follow the promptings of the Holy Ghost" once we have been baptized and given the gift of the Holy Ghost. It's all simple enough, right? Reject the bad, embrace the good.
Unfortunately for me, I could never quite sort out my thoughts so neatly partially because there was a little more to the story. In church I was taught time and time again that Satan had no power to know my thoughts but God knows my thoughts perfectly. I remember puzzling constantly from before I was baptized to the day I said my last prayer how the hell Satan managed to carry on such a wonderful debate with the Holy Ghost when the debate in question was all in my head. God's fine in this situation because He's got his Spirit alter ego tracking my every thought, but how could Satan have any ability to offer counter points to the inspirations of the Spirit if he has no idea what I'm thinking? How could Satan even know what the topic of debate was at all? As far as I knew the Devil & Co. were just bombarding me with everything they had at all moments hoping that something - anything! - they had to say would stick. The only way "those unhappy spirits" would have any idea that they got through to me was if I immediately did what they suggested. I can only imagine their disappointment when all they could get me to do was sneak a bowl of Blueberry Crunch instead of killing my entire family and torching the house. The Spirit must have been very strong with me!
Actually I never really felt like I was dialoguing with the Holy Ghost. Seriously, not once. I wanted to so badly. I wanted to have at least a story or two about how God inspired me to hurry home and upon arriving home I find an emergency situation that I'm able to resolve before it gets out of control. Or at least a story about finding some lost car keys! But I got nothing. There was never a Still Small Voice inspiring me to do kind things or filling me with greater light and knowledge. It was always me and the Devil fighting over stupid shit like sneaking a snack vs. waiting for dinner. That's one of the worst parts about the way Mormonism teaches resistance to evil: it almost always has something to do with "physical appetites".
In my experience the temptation Church leaders warned us about the most by far was sexual desire. Enticing your sexual pleasure was Satan's ace in the hole, and it was your job to fight off all improper thoughts of an erotic nature. Sexual acts, which rank just below murder and the denial of the Holy Ghost, were grievous enough to warrant a trip to the bishop's office for a very uncomfortable confession. Remember, guys (and gals), that "the natural man is an enemy to God!" so please don't do anything you're biologically inclined to do.
And yet other bodily impulses were not so severely monitored. Sneaking sugary cereal wasn't going to win me any points in the Celestial Kingdom, sure, but unless you're fasting you really shouldn't refrain from eating. Urinating and defecating are always okay and should be taken care of in a timely fashion. Washing up when you feel uncomfortably sweaty or dirty is encouraged and so is sleeping when you're tired. Oh, you should also clean out your nose if you have a little something up there giving you problems.
I could never sort out what was temptation, what was inspiration, what was natural me, what was brain me, and what was spiritual me, which all resulted in doubting myself ALL THE TIME.