Anon has threat-sensitive anxiety.
The message is an unexpected intrusion, with right answers and wrong answers but it's not clear which is which. "Morning beautiful! π π" Is insincere because anon doesnt feel that cheerful, and anon lacks confidence in his ability to be convincingly insincere, as well as feeling like a fraud for having to pretend to be happy, AND is acutely reminded of his inability to be happy. "Morning" is muted and emotionless, bound to be inadequate, possibly signalling anger or discontent. "π " Is definitely a no-go, probably. Non-response is also just kicking the can down the road, eventually he has to respond, AND come up with an excuse why he took so long.
Anon has just woken up and immediately needs to deal with a scenario that his threat-model doesn't cover, and where a wrong answer will have real-world consequences, possibly derailing his whole day and impacting his relationship over the longer term.
Anon is exhausted from the constant wargaming with all the minutiae of life.