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.
YMMV: Zoo Tycoon
Base Breaker: Zoo Tycoon 2013. Some fans hate the fact it is on the Xbox as opposed to the PC, others are just happy to have a new Zoo Tycoon at all.
Further broken by the fact that the new game has 101 animals on the Xbox One and a comparatively paltry 65 on the Xbox 360. Xbox One exclusives include fossa, both of the available species of mongooses, and every single antelope except for one, which is a DLC. (Notably, the game doesn't include any subspecies of zebra, a standard zoo animal. Future DLC, most likely.)
Big Lipped Alligator Moment: Santa and a Witch appearing for Christmas and Halloween for ZT1. They fly across your screen for a split second on the in-game Halloween and Christmas. If you're quick (or if you pause the game) you can open the foliage menu and buy special plants- a jack-o-lantern on Halloween and a Christmas tree on Christmas. (Waiting until December 25th in-game is the only way besides cheating to get a Christmas tree, which is the preferred foliage of the reindeer.)
Complacent Gaming Syndrome: Regardless of how beautiful or detailed a pre-made map may be, expect one of the first actions when loading up a scenario to be bulldozing everything except for the initial path.
In the first and second games, it's possible to buy a male animal just long enough to let it breed with a fertile female, then undo the purchase action so it vanishes and you get your money back. Pregnancy, if achieved, doesn't go away when you do this.
It's always amusing when you place a predator in a prey animal's enclosure, and the prey animal responds with a happy face above it's head. (The game uses this to indicate a animal's happy with your decision.)
Hell Is That Noise: The "whoah-who-hoa-ha!" sound the adult male guests make when they get attacked by animals is pretty unnerving, especially when you realize you'll be getting unhappy guests.
Most Annoying Sound: *dee-doop* 'Zookeeper 1 can't reach the food dish!' *dee-doop* 'Zookeeper 1 can't reach the food dish!' *dee-doop* 'Zookeeper 1 can't reach the food dish!'
What makes this especially annoying is that whatever is 'out of reach' tends to be perfectly fine. The problem appears to be with distance, not with any real obstacles, as the game seems to treat being a certain distance from something as it being inaccessible.
*dee-doop* "Lion 1 can't reach the food trough! It may be too close to another object!" tends to pop up when you have food troughs shoved up against a wall. While the animals can still access one side of the trough, they sure don't realize that and assume that because one side is blocked, the rest of it is too.
The adoption system in Challenge Mode in Zoo Tycoon 2.
In the first game, the excessive amount of time given to complete some scenarios. In some cases, it's so bad you will spend more time waiting for the time to pass than actually doing the stuff required to complete the scenario! Fortunately, you can make the game play in windowed mode so you can leave it running while you do other stuff, but it's still annoying and ridiculous. Thankfully, the devs seemed to catch on, as some of the missions in the expansions and all of them in the sequel don't have time limits.