Mario Party 8 has King Boo's Haunted Hideaway, which is a randomly-generated map that changes each time you play it. The AI seems to not plan ahead at path forks, and it will choose a path even if it knows the next fork on that side has one path leading to a dead end and a Whomp blocking the other, and that it doesn't have enough coins to pay the Whomp's toll.
Basically, when the computer in Mario Party isn't being a cheating bastard, they have an IQ of -8. They will buy items for easy access to the Star, even if the cost of the item puts them below the coins needed for the Star. All the freakin' time.
It gets worse on the investment boards like Windmillville and Koopa's Tycoon Town. Most of the time, they will invest every single coin they have, even if it's not necessary or if they can't actually become the top investor, doing nothing but helping the other players. It makes it impossible for computers to invest on the building that is right next to it, unless they keep getting low rolls and winning minigames.
The computer will also use items to roll multiple dice blocks to get to the star when they don't have enough coins to buy a star.
One particular case of the HARD AI in the first game being incompetent is pointed out by The Runaway Guys when Peach, otherwise a luck-manipulating bastard on Hard, proceeds to get the Ground Pound Coin Minigame and use a total of 9 ground pounds to find the 5 "correct" posts.note For those unable to watch the video, this is out of 12 posts, and all 12 of them were plainly revealed at the beginning of the minigame. The pattern went something like "pound sharp post, pound 'correct' post, repeat". It turns out that the AI is programmed to do this.
During their video of "Chilly Waters" the AI (Wario in this case) makes even more stupid decisions. He passes by the star multiple times and at one point, he duels Jon for one coin (by using a Dueling Glove he bought for 10 coins). Jon actually questions if the game is broken because of all the dumb decisions. And again, this was on hard mode!
In Getter Love!!, while you're pitted against three AI-players in normal mode, you'll have an advantage of your own in this already difficult game. For one thing, AI-players epically suck at mini-games, letting you win almost every. Single. Time! (Except for the whack-a-nerd game and the quiz game, the former which they're actually somewhat good at, the latter which requires you to understand what anyone says in the game.) Also, instead of using offensive cards strategically (like to fuck up someone else's date and possibly prevent them from declaring their love to someone for that turn), they tend to just use them on whoever has the most flourishing relationship with their girl of choice. Sometimes, if they challenge someone to a mini-game and win, one of their options includes changing their name, which has no effect on the gameplay, and they'll actually choose this every now and then. Most egregiously, whenever you talk to one of your opponents, you actually have the option to give them an item card or memory-unlocking topic, for no gain of your own, which they'll do every once in a while. Really, what's the point of doing that, or even such an option being there?
In Fortune Street, any A.I. with an E rank will happily give you their property for what it's roughly worth should you offer. Even if that means increasing the value of your current properties to insane heights, making it possible to pay a lot more back in one turn.