Lance Parkin, in his retrospective on Doctor Who that appeared in "Time, Unincorporated" from Mad Norwegian Press, said that the Fifth Doctor was "subtle, restrained [and] sweet" as opposed to the "brash, exuberant, nasty" Sixth Doctor. With all due respect to Lance, and to the millions of other Doctor Who fans who share this view...you're all wrong. Peter Davison is subtle, restrained and sweet. The Fifth Doctor is rude, condescending, and temperamental. You just don't notice because he's being played by Peter Davison, who could murder puppies in the street and still have passers-by saying, "Awwwwww..."
Seriously, go back and actually watch any Davison story. Pay attention to what he says and does. He shouts, he blusters, he snaps, he's constantly berating his companions; he's doing to Tegan the exact same thing that the Sixth Doctor does to Peri, only Peri always looks like she's about to cry whenever he does it. (By the same token, the silly throwaway short "A Fix With Sontarans" shows that the Sixth Doctor, paired with Tegan, becomes half of a great comedy double act. There is a parallel universe where Janet Fielding decided to stick it out for one more season, and it's awesome.)
This isn't meant to be a slight on Davison; he consciously modeled his character on Hartnell, and did a magnificent job of using his natural charisma (see point A, above, about puppy-killing) to make the Doctor sympathetic even while he was spiky and temperamental. But please, Doctor Who fandom, stop saying that he was the "nice" one. He was just as big of a jerk as Colin Baker, but Baker wasn't as good at hiding it.