The bots in League of Legends are dumb. There's certainly no other way to describe them. Even the recent bot update couldn't change that very fact. The funny thing about this however is that whenever I play the Co-Op vs. AI mode, we human players normally do some pretty stupid things ourselves because we expect these bots to be so completely helpless. Unintentionally, this usually resulted in extremely funny and somewhat surreal moments when the planets suddenly seem to be aligned for the bots and all of a sudden they get to pull off some slick moves themselves.
Take this situation for example. The bots are pushing the bottom lane together and my team started to ambush them from in front and behind them, thus trapping them in the lane. You know that the bots can't make the proper decisions about what to do so some of them started fleeing away in an attempt to escape the ensuing massacre thus we were able to kill off three of them rather quickly. But we ourselves didn't focus our attention on the real threat in the bot's team composition: the Karthus bot. Not only that, our positioning was horrible and most of my team members were standing on top of Karthus' defile, which is a nasty area of effect damage over time spell. Then Leona Bot casted her ultimate, stunning and slowing four of my team members and all of a sudden... Karthus Bot with a quadra kill! It's the hilarious situations such as this one that keeps me coming back to fighting the bots. Sure, unless you are not paying attention whatsoever or that you are playing with people who are brand new to the game, it is impossible to get beaten by the bots. But that doesn't mean that you will not have a good time watching them struggle and you know that we all need a good laugh every once in a while.
That Karthus Bot will definitely be bragging to his bot friends about this one.