Why?

An ad for "An Angel's Trail"
a Charlie's Angels episode aired in 1980

In 1979, Shelley joined the cast of the biggest show on TV, Charlie's Angels, as the newest Angel - joining incumbent Angels Jaclyn Smith and Cheryl Ladd. Farrah Fawcett joined the cast for three episodes during seasons 3 and 4. "An Angel's Trail" was the last episode Farrah did for Charlie's Angels; and it was the lowest-rated of her comebacks. Charlie's Angels was becoming stale; bad scripts and repetitive plot lines were killing the show. Shelley was a breath of fresh air when she came in, but her character Tiffany Welles was grossly mishandled and underused.

Cheryl Ladd, Jaclyn Smith and Shelley Hack
from one of the sexiest Charlie's Angels promo pic set ever

Shelley was blamed for the decline in the ratings that season. But was it really her fault? The show had already declined the previous season; yet the show was never improved script-wise or plot-wise. They said she couldn't act; but she wasn't bad in the TV movie Death Car on the Freeway and in her Love Boat guesting (she was quite impressive in this one) - both of which came out during her tenure as an Angel. She wasn't given much to say or do during the first half of the season - when she hot property and everyone wanted a piece of her. Only when the ratings began to go south was she finally given more lines and more significance in the plot - and she wasn't bad at all, mind you. You could actually see her taking over from Sabrina Duncan as the head Angel in her last episode "One Love... Two Angels: Part 2". The big question is why wasn't she given a chance to shine during the first half of the season - when she was the hottest name in Hollywood and everyone wanted to see and hear more from her? It was Charlie's Angels after all, and she could obviously handle the material.

watch a minisode of "An Angel's Trail" at
An Angel's Trail 1980 | Charlie's Angels mini episode | Farrah Fawcett guest stars
https://www.youtube.com/watch?v=PDBDys0NGY8
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