A side-effect of time-travel. Those who have experienced time-shifts in any capacity – into the past or forward – inevitably develop a superiority complex towards the native (non-time-traveling) people of that time.
Some have argued that this – and all other time-anomaly related psychosis – are purely psychological, that only those with knowledge of their time-shifts develop this attitude. This comes from research done on subjects that were sent through time without their knowledge. It must be noted, though, that this research is flawed, since by its very nature, data is nearly impossible to collect.
General psychotic behavior is reported by nearly all time-travelers and those who have observed them. Many Chronoteurs have claimed that only knowledge of their time-shifts (or their direct effects) caused any psychological issues, and that on missions that they time-shifted unknowingly, they noticed nothing. This has also been backed up (and also denied) by those observing their behavior.