YMMV / Hay Day

• Fridge Brilliance:
  • The animal shelters are dirty and poorly maintained when you first get them, but as you obtain more animals, they become cleaner and newer-looking. More animals means more visitors who come to see them, which means more money for you to renovate the shelters!
  • In the Town, visitors to the Spa will sometimes ask for cans of beeswax. Why? For waxing treatments, of course.
• Game-Breaker: In the Valley, collecting sanctuary animals makes it easy to rack up enough tokens to be able to buy the 30 diamonds at the end of the valley season. This is because you can get large amounts of tokens (up to a few hundred of each color) for delivering three animals at a time to the sanctuary, while filling regular orders only results in very small amounts of tokens (less than 20).
• Germans Love David Hasselhoff: The game seems to be really popular in Brazil, judging by the number of players' farms that have "Fazenda" (the word for a Brazilian farm or plantation) in their name.
• Memetic Mutation: On the r/HayDay subreddit, joking about the farm visitors being Ax-Crazy due to their tendency to ask for large amounts of axes and dynamite.
• Scrappy Mechanic:
  • One way to earn coins and experience is to fill boat crates. 4 hours before a boat appears, you're told what items will be needed to fill the crates, which gives you time to produce said items. Boats can also ask for multiples of an item with a ridiculously long production time; for example, a single jar of blackberry jam takes 8 hours to produce—and it's possible for a boat to ask for 8 jars of the stuff!
  • Farm visitors are usually not worth selling your items to, because they offer to buy your items for less money than what you would get if you sold them to other players. The only time it's really worth selling to them is during events that have them pay double what they normally would.
  • As soon as you reach the required level to be able to make an item, boats/truck orders/town visitors can ask for that item, even if you don't actually have the machine that produces it. Lord help you if a puzzle-piece boat asks for one of those items.
  • Many players find the Crops Bonanza event frustrating because it causes all planted crops to yield 3 crops instead of 2 for the duration of the event. While useful on paper, it can cause your silo to fill up really fast, especially if you're planting fast-growing crops like corn and wheat, and especially if you're a lower-leveled player with less silo space. It doesn't help that you can't get rid of them quickly by selling them, since every other player also has tons of surplus crops at the same time. A similar event causes 3 random crops to yield 3 instead of 2 for the day, but is much less complained about.
  • Boats can ask for two different items that require the same ingredient — for example, a boat that asks for orange sorbet and fruit salad, which both require honey. You can only have one of each machine (with the exception of the sugar mill, which you can have two of), and each machine can only produce one item/ingredient at a time. Truck orders and town visitors can also do this, but it's a bigger problem for boats since filling them is a Timed Mission.
• That One Achievement: The achievements "Turbo Trucker II" and "Turbo Trucker III", which require you to fill, respectively, 20 and 30 truck orders in the span of 30 minutes. This timespan doesn't give you any time to make items on the spot, so you have to fill your barn ahead of time with as many unique items as possible, hoping the orders don't ask for something you don't have (and they almost always ask for multiple items). If you're trying for this achievement and run into an impossible order, you can delete it...but it takes from 6 to 30 minutes depending on your level for a new order to replace it (but even at Level 48, the replacement time is still 30 minutes). So, depending on your level, you could have only one shot to fulfill each replacement order. Or zero shots.
• That One Sidequest: Getting three mastery stars on some of the machines can be really hard.
  • Coffee Kiosk: All the products take very little time to make, which means each product adds very little to the required number of hours for each mastery star. They also require coffee beans and/or cacaos, which requires you to buy coffee bushes and cacao trees, then wait days before being able to harvest them.
  • Pasta Kitchen: No pasta product can be made solely with field crops or animal products; all of them require cream, butter or cheese, which need to be made in the Dairy first.
  • Donut Maker: Plain Donuts take a mere 15 minutes to produce, and all other donut products require them as an ingredient. They’re made with White Sugar, which itself takes 34 minutes to produce in a fully mastered Sugar Mill. Even if you have a lot of White Sugar, you will probably run out of it very quickly when trying to make lots of Plain Donuts.
• Unfortunate Character Design: More like Unfortunate Item Design. The Pancakes are covered in red liquid that is presumably supposed to be strawberry syrup, but looks more like blood.