I remember wanting to love Dr Who even before it was broadcast. The TARDIS was great, but the first series was disappointing. Like so many others, it was the first sight (and sound) of a Dalek which vindicated my hopes.
I think Doctor Who was finding its feet in the Hartnell era and it was Troughton who really first defined the character to what he became later.
In the Hartnell era, the Doctor was a grandfather I think, looked old (although Hartnell was much younger than he appeared, thanks to the war etc) and seems to have been human.