I started with Everton this year. I don't remember the goal, I think it was qualify for CL. A little past half season, I was sitting mid table. Things weren't going well, loss after loss. I got fired. First time ever in FIFA
Of the jobs available I took Cardiff to avoid relegation. They were right there in relegation zone, no surprise. I wasn't able to keep them in the premiership. They kept me. Next year goal was to get back in. I lost in playoffs and didn't make it. They still kept me.
I've had enough lower league action (especially with the longer season and 15 min halves). No jobs available, so I started a new CM with Newcastle. Goal was CL again. Finished 5th and went Europa. They kept me.
This season it's win Europa, go to CL. I doubt I will win Europa but potentially will make a good run. League is tight race. Top 8 within 7-8 points or something. One game ago I was sitting at 5th spot with 3 points below first and 3 above 9th (kinda crazy to me, and really fun). I don't remember how it was looking after my last game.
But I think they're somewhat flexible if you don't meet the goal. I think it's more important to stay out of losing streaks and look bad for a long period of time. And finish somewhat close to the goals. Afterall 10 or so clubs start the season dreaming about CL and only 4 make it. Not all 6 remainders fire their coaches (although this year it's been a little crazy in BPL in real life).
It's interesting to trick the board with the above mentioned method. I like the goals, and they're not unrealistic with the teams I've played with. But I can see some people (something was mentioned above in the lines of this) not wanting to worry about the managerial aspect of CM and play the game. For that I actually have a good suggestion that I've done in the past. I start a player career, set my camera to regular (not be a pro). At the beginning of the game I pick to control the whole team rather than just myself. So you actually have a manager taking care of stuff you don't have to worry about. You're role playing your be a pro but control the whole team in the meantime. I enjoyed it quite a bit.