Among the Doctor Who fandom, the shipper contingent devoted to Billie Piper's Rose Tyler and David Tennant's Tenth Doctor is among the most passionate. So after Rose went off to another dimension, in theory bidding the Doctor an eternal farewell, his next traveling companion would face some seriously unfair fan comparisons. Unfortunately for Freema Agyeman's Martha Jones, many of those came from former showrunner Russell T Davies and his fellow writers.
And this was hugely disappointing for many reasons.
For starters, Martha Jones was amazing. She was an actual proper real doctor, and she was smart, and funny, and she loved Harry Potter, and she saved the world a lot. She was a boss.
So what did they decide to do with her? Turn her into a lovesick puddle for the entirety of her TARDIS tenure.
The Doctor himself didn't help matters. He was too busy ignoring the vivacious pillar of human perfection before him (not that it should even matter--CAN EVERYONE QUIT TRYING TO BANG THE DOCTOR? DAMN) to be all pouty about Rose. This is hugely irritating to those of us non-shippers who actually thought what the Doctor was about to say at Bad Wolf Bay was "Rose Tyler, I love you TOTES AS A FRIEND."
That's why in a season where she literally walked the entire globe to save the Doctor and the entire universe, the best and healthiest thing she did was to walk away.
Luckily, the writers realized they'd wasted this incredible character and brought her back ... to waste her all over again. But we love her anyway. So, Martha Jones, thank you.