Slow (digital) services are annoying. Who has the time to wait? Nobody. However, some of them have to be deliberately slow.
According to the (Walter) Doherty threshold, people are most productive when interactions with a computer take less than 400 milliseconds. Any longer, and we feel like we have to wait for the machine, thus limiting our productivity.
Contrarily, when something looks laborious and takes longer, it increases trust. Human resources -, travel – and medical technology often craft delays on purpose while returning reports. Referred to as the labor illusion; we tend to value results more when they’re presented to us with a small delay.
Timing is everything. Sometimes 400 milliseconds more or less is all it takes.