My trainer at my current job was supposed to train me on an experiment.  I believed her when she told me I was learning too slowly.  Turns out she was deliberately ignoring my training because she didn't like me. 
I didn't get a promotion I was up for because the person training me disliked me intensely. 
user
oooh no  thats was so bad 
assistant
Thanks.  It was pretty awful when I found out she did it on purpose.  I thought I was just bad at the job.  
user
don't worry there's always another chance
assistant
Yeah, I'm training with the doctoral students now and it's going better. 
user