Mine has learned that if he asks to be let out for the toilet, even though he can open the door himself, someone will get up and let him out, and he can use your attention as an opportunity to ask for treats/an extra walk/a second dinner/playtime. If he asks for these things when you're busy, and it's not playtime/walk time, or dinner time, he will be sent to bed, so he doesn't ask for any of these things anymore; he asks for the toilet instead.
He is now asking to be out every 2.3 seconds. All day long. Every day. And I can't tell when he genuinely needs the loo or when he's going to make a detour to his food bowl/the treat drawer en route to the garden.
Come and tell me your dog's annoying habits to distract me from locking mine in the garden for the rest of the day.