For puzzle games or games incorporating puzzle solving elements, players tend to take "hints" seriously. They pay more attention to observing the environment and try to learn as much as they can through interaction with the game. Some elements in a puzzle game may seem to be significant; they capture a lot of attention from the player. However, they turn out to have minimal impact in solving the puzzle. This ineffective learning is frustrating, especially when solving puzzles .
Little Inferno is a game where the player burns all kinds of stuff in a fireplace. The player uses money to buy objects to burn from the "categories". Burning objects earns various amount of money. If the player burns two or three objects together that happen to form a "combo", that combo turns into stamps. Moreover, certain number of combos are required to gain a new category, which is how the player proceeds through stages of the game. The combos are given implicit names, such as "Watching You". So the most significant puzzle solving in the game is to figure out what the combo is and burn it. However, the game has its setting in a neighborhood. So occasionally, the player gets mails from the neighbor, sometimes asking or sending package, but more often, chit-chatting. The player has no way to add dialogues, just clicking through the whole mail.
I think the neighbor feature is a good way to add interaction in the game with other characters. But the features would have to be more engaging in order to add to positive gameplay experience. Since this mail feature is so irrelevant to the core game and pops up randomly, it disturbs immersion for the player.
Below is a screenshot of a typical "random" mail.