I was particularly inflexible and rule-bound when I was young. I liked (and still do) to do things in a specific way with a specific timetable. I also made up specific rules for myself to follow. Unpredictability is definitely not something I would like to invite into my world (I grrrr surprises, but of course!).
Since I've grown into a responsible adult, this particular trait's getting a lot better and won't affect my line of work these days. Some telltales are still there, but people can only see them when they're allowed to take a closer look at my daily routines.