Not open the messages all the way unless you are in the mood to reply.
The appearance of “seen” has created a new phenomenon: opening messages partially, having a peek at the beginning of the message and assuming the rest so that the other person doesn’t get a “seen”. Also when writing a message, be aware of how your first sentence begins, because this is what the other person will be halfseeing. When “seen” first appeared people thought they would have to answer messages immediately. But it actually didn’t make the culture of answering change, it only made visible what we already knew: people don’t always reply straight away. Even though it became more acceptable not to reply immediately, the technique of halfseeing is very commonly used. Those who don’t find the beginning of the message to be enough but still don’t like to reply straight away may benefit from seen blocking apps.