It's tempting to say that the above picture says essentially all you need to know about Peri, but that's not really fair. The truth is that she worked fabulously with Peter Davison. For one thing, her character simply worked better with the character of the Fifth Doctor. She's a little bit spoiled and a little bit difficult, but that's exactly the dynamic that brought out the best in the long suffering yet still patient Doctor number five. Plus, underneath her frequent complaining, it's perfectly clear that the two of them care about each other deeply. The dynamic changed for the worse when the Sixth Doctor arrived. What had been a setup of one character complaining while the other sighed deeply became two characters just endlessly bitching at each other. Which is even less entertaining than it sounds. Not helping matters was the change of format which meant the regular addition of padding scenes to make up time. Which meant that they became scenes of two characters bitching at each other while not furthering the plot in any way. Brilliant.