eX, baby. Sounds cooler and kinda mysterious. X marks the spot. I'm also guilty of saying it as eX in my mind before saying out loud Ten. And for grammar Nazis, I will continue to put "an" before X instead of "a."
I wished Apple just called it that not to diss people who love the #9 like what Microsoft did. I hope next year's iPhone will be called iPhone XI but I would still call it eX-One. The s models ruined the order. Only iPhone 4 was named properly for its time of release. We should be on iPhone 11 right now. Who cares if it looks the same as the previous? Automobiles look similar to their predecessors too.
So if you ever break up with it for a newer one, you know what to call it. The eX. I used to mistakenly say OS eX, so I will call it iPhone eX. Although about 40-50% of the time I also do say Ten. It's like eX is its alias/nickname we can give it similar to Barbara or Babs. It's not like we call our friends and relatives exactly what's written on their birth certificate.