Callback-oriented code is different. With by-the-book OOP code you're still executing one line at a time. You might be teleporting in space, which has its own

Callback-oriented code is different. With by-the-book OOP code you're still executing one line at a time. You might be teleporting in space, which has its own problems, but your code still reflects the order of execution. With callback-oriented code you're teleporting in space and time. They can both make it hard to trace the path of execution. At least with OOP code you have a sensible stack trace, though. ;)