Star Trek: 10 Crazy Facts About The Trill
1. Past Lives Are Separate
If you're a Trill who wants to be joined with a symbiont, there a lot of hard and fast rules you need to follow. The Trill Symbiosis Commission developed and maintained all of the rules to benefit both the symbionts and the Trills. But of all the rules, the biggest one was no connections with a symbiont's past lives.
When a host and a symbiont were joined, any and all connections to previous lives were considered null and void. If they weren't, a new host would end up paying old debts for their entire existence. Since Jadzia was the eighth host to the Dax symbiont, there were a lot of potential old debts to deal with.
As it turned out, Jadzia was the absolute worst at observing this rule. Her commanding officer was Ben Sisko, whose best friend was the previous host Curzon. She reconnected with another previous host's wife. Jadzia even got involved in a Klingon blood oath Curzon was part of.
Jadzia wasn't really great at following most rules but she really didn't seem to care about this one.