Planet of Giants is such a fun story because it's just like. Watch Ian and Susan be worried about signboards and matchboxes. Watch the First Doctor falling over and screaming while trying to hold on to a matchstick. Watch the gang tremble in fear while trying to hide from a cat. Barbara bruises her knee on a paper clip. The Doctor and Susan climb up a drainpipe and stand in a sink. The gang tampers with a phone and starts a fire ('Yes! That’s it! We’ll cause trouble! Start a fire [...] there’s nothing like a good fire is there...[the Doctor trails off with concerning hee-hee-hoo-hooing]'). They manage to avert the circulation of a deadly pesticide and thwart the machinations of a ruthless businessman. Oh and they're all about an inch tall at the time, in case you were wondering.
While watching An Unearthly Child I was like "while it's definitely fascinating to see how far Doctor Who and The Doctor as a character have come after so many reveals, retcons, and recontextualizations. It doesn't change the meaning of the story all that much" and then The First Doctor said fear makes a companion of all of us and my mouth dropped to the fucking floor.
This scene of Vicki being worried about The Doctor leaving her and that she's a problem, but the First Doctor being like no absolutely not I'm just trying to keep you safe and out of danger s sweet. It's a tiny nugget of cross-serial character growth and communication that I'm here for.