It's been switching back and forth between these behaviors for at least six months now. It's not like I can't afford to replace it, or like it would be a terrible bother to do so. It's just that when my toaster develops a mind of its own, I feel like I should spend some time trying to get along with it, instead of just murdering it the first time its opinions become inconvenient to me.
Today I patiently pressed the button back down four times and then it miraculously decided to cooperate and toasted my bread just perfectly. Now I'm eating a delicious grape jelly sandwich.