The side characters you only see in that one episode; Sally Sparrow, That REALLY cute UNIT guy in Sontaran Stratagem (still pissed they killed him off. UNIT DON"T MEAN RED SHIRTS!!) Malcolm Taylor. The Companions of the Day if you will.....well....cept that UNIT hottie he was just there as eye candy but, he was good. They show how the Doctor touches lives and how -mostly- he leaves them better than they were. Better for their planet they live in. Most go on to do great things.
Rory has also wormed his way in. Like Rhys. They are good guys. Really good guys and have no problem countering the Doctor. I find him to be the better version of Mickey. Mickey annoyed the hell out me before he became bamf. Rory was BAMF from the start. He was already working on what was wrong with his patients Helping the Doctor.