It is said here that the phrase "get to do something" implies to have the opportunity to do something.
But is it the real meaning of the expression in this Garfield's sketch ? "Next time I'll have the opportunity to pick what we do!" seems strange to me.. Isn't it a way to express a future action ?
Having suffered Garfield’s smack, the spider tells him that the next time boredom strikes, he will get to decide what they should do. In this context, get to do implies an opportunity or chance to do something or take action. The spider says that next time, it will be his chance to decide how they combat boredom (cos he clearly doesn’t want to be at the receiving end of another smack).
You can read more here: https://english.stackexchange.com/questions/16104/get-to-do-something
