Michael Dorn has said he wanted the role in Next Generation because he thought it would lead to films. Denise Crosby didn't get that memo. On a DragonCon panel Crosby asserted that she had left the Star Trek series to broaden her horizons, or some such crap. Frakes said something to the effect of, we see how that went. Crosby stormed off the stage incensed.
Whatever the reason, Crosby asked to be released from her contract in the first season. The episode "Skin of Evil" featured the demise of Lt. Yar. It was one of the worst TNG episodes of the series.
Denise hasn't had a bad career since leaving the series, in my opinion. Many may remember her from "Pet Sematary" the Stephen King flick. Tobe Hooper's "Mortuary" was a bit of a bomb. But Crosby has a lengthy list of film and television credits. And most recently she's been seen on "The Walking Dead."
I hope you enjoyed this Star Trek installment of Rule Five. Next week I hope to bring you a couple of horror vixens who made things bump in the night. IYKWIMAIKYD