Suggestions for analyzing data for being unusual

I have a set of data where a group of individuals selects each day whether it was a 'good', 'neutral', or 'bad' day. I am trying to come up with a way to look at each individual's data and determine whether their incoming daily response is outside what their 'normal' response pattern is. I have been exploring using a weighted average approach where each day is scored as a weighted average of the previous XX days responses. I then tried to put this onto a control chart but the responses across individuals can be so different that a formula that works great for one individual doesn't work at all for another. The biggest issue I am dealing with is what one person thinks is a 'good' day is another person's 'neutral' day. Some individuals select 'neutral' as a baseline and go up or down from there while others select 'good' as a baseline and go down from there.

Does anyone have any suggestions on how I can take this data and determine on an individual level, based on their historic responses, whether their most recent responses are unusual?