I know most of us aren't managers or pop stars and thus are not allowed to critic others career decisions but let's try nonetheless.

Everybody makes mistakes, everybody has those days.

If we're talking about music.

Justin Bieber and Lady Gaga for sure

Well we have two scenarios, leaving your manager when ready and flourishing like no other (Beyonce) or leaving your manager prematurely and digging up your own grave (Gaga)

Gretchen. That adult movie she did... She let her career roll downhill

GaGa.

Angelina marrying Brad, she's catalogued as a "****" for the rest of her life. It's so sad.

Justin and Gaga as well if she releases Venus as single

Your topics are definitely my favorite here Anyway of course Gaga. ARTPOP that's it.

I don't think Beyonce leaving Matthew was a mistake considering she's making the music she wants to make and it really didn't affect her career THAT much unless you think 4's underperformance is more important to her career than it is, despite doing bigger and better things after it.

Diddy

He's dropped the ball on a lot of artist's with huge potential for greatness

Xtina made so many mistakes in her last eras.

Well it depends on the outcome. If you still have a successful tour, multiple massive gigs, and huge endorsements, It is not a mistake. Which leads me to say, Beyonce can't make mistakes