The stuff that's bold is not illegal, and not violateable depending on the circumstance, but is opinion, and the stuff in red is opinion.
Let's start with the first red one. That's an opinion, if you fly to the same place five times a day, in the same airplane, is your preflight going to be all that involved? No. You're going to do a quick walk walk around, nothings bent, oils good, you're gone. Why? Because at your post flight yesterday you check the airplane out good before you tucked her there's no maintenance in the book, and nobody's clearly backed a forklift into it. A preflights quality is definately something that's subjective. And since its damn near impossible to know all available information pertaining to the flight,
all of our preflights probably aren't too legal either.
Number two, that is subjective there, I know plenty of people who's fuel management is "burn a tank dry, if I'm not over half way there its time to divert or turn back." Is constantly switching tanks every 15minutes any better? Your fuel will be balanced, but you'll be sweating when you have 4 gallons in each tank and the gauges are practically on empty.
Bolded #1, what are dangerous conditions? Slick runway? Gravel? Narrow? Up slope? Crosswind? There is no definition of "takeoff into dangerous conditions," who chooses what is dangerous, nobody. Look, I know people who think a 3000' runway is short, its not, and its not dangerous. None of things are dangerous, not even in combination, they only become dangerous when the extent of the variation exceeds the pilot's ability to safely handle them.
Bolded #2, not illegal. There are plenty of times part 91 when I zip back along dodging moose and trees and looking for fish or bears. If you are 500' from persons or property, you are golden. Your reaction time for reacting to an engine failure maybe reduced, but you're really not any less safe providing you maintain clearance with the ground.
As for the others, booze is bad, so is overweight, and that watch thing is rediculous, however, ice happens. Its not something you want, but sometimes even when planned around you can still run into it. Based on where you are at, and knowledge of terrain, it sometimes may be better to keep on truckin than to turn around and fly back through it, try to keep an open mind. By the way, every time I shoot an approach that terminates in a landing I descend below minimums.
These posts that just blanket statement things tend to aggravate me, though I'm guilty as the next guy for posting them. There is more than one way to skin a cat, and vary few things are set in stone. Sleepy time.