These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crack is Cheaper: Some addons for the simulator (planes, scenaries, etc) are as costly (or more) than the game itself, partly because designing a good plane is extremely hard, programming-wise, not to mention having to pay the license for the use of the jet in the simulator. Luckily, there's lots of freeware addons you can use, too.
Germans Love David Hasselhoff: Judging by the amount of mods, addons and additional planes you can buy or download for free, the franchise seems to be very popular in Germany.
Misblamed: Somewhat, as the September 11, 2001 terrorists trained with this program for carrying out the attacks, even if they also trained with real planes. This is possibly one of the reasons, along with lower sales and Microsoft shifting from PC games to Xbox consoles, why Microsoft decided to kill the series.
That One Airport: Just like in Real Life, some airports are notorious for being a pain to land on them:note The list excludes airports whose landing conditions relays on artificial means, like the Ronald Reagan Airport in Washington, DC, due to the large amount of no-fly zones the pilots had to avoid and one of the reasons that airport is off-limits for non-American planes.
The Kai Tak airport in Hong Kong (ICAO code VHHH, now used in Real Life by it's replacement, the Chep Lap Kok airport, whose ICAO code in FS is VHHX), despise being closed in 1998, still appears in all recient versions of the game, and both the real one and the videogame version of it are the most difficult airports to land over there, since you have fly over Hong Kong City and sometimes over their buildings. No wonder why it was closed.
Trying to land into an aircraft carrier. For an extra challenge, try to land into one with an airliner.
The Sunan Airport in Pyongyang, North Korea (ICAO code ZKPY) is an inversion of this trope: The most annoying part of this airport is taking off, since the runway is too far from the boarding gate and you need a lot of time just to be able to take off. On the other hand, landing on this airport is very easy.