Digimon Masters/YMMV


 * Scrappy Mechanic: Dear lord, the egg system. You have a very small chance of getting a mercenary egg from a given Digimon (assuming they're a member of an available family). This alone could take hours, but then factor in the data-insertion system. You need a certain number of data, again acquired through slightly more common drops, and need to apply it to the egg at least three times to get a new Digimon. The amount of data varies from species to species, but the most popular or desirable Digimon tend to take the most data. The problem is that this insertion process can randomly fail and waste your data. On top of that, there's a completely random chance that failing might cause the egg to break. So you might break it on the first attempt, or fail but not break the egg after twenty times. The system is heavily weighted against allowing players to acquire new Digimon, and many have demanded at least a slight increase in the odds so as to not waste so much time and effort. Ultimately, many players find it easier just to buy an egg from the cash shop.
 * Relatedly, the drop system. After reaching a certain level above them, Digimon have a hugely reduced rate of dropping items. Have fun getting a Dokunemon egg or dragon-species data after a certain point, since it'll take hours, if not days. While this system might be in place to abuse getting too much material too easily, players still cry foul since the Korean version does not have this cap implemented at all, so players of the global version expect fair treatment in that regard.