Robot

Both involve a giant robot.

The Stolen Earth/ Journey's End

A companion who had previously declined to continue traveling in the TARDIS (Mickey in The Age of Steel/ Harry in Terror of the Zygons) makes another appearance.

The Keys of Marinus

One of the leads disappears from the story, mid-way through the adventure.

Adam Mitchell almost changes history, with no ill effects, in the end, but gets booted in the end. Rose completely butchers history, almost destroys the universe but she doesn't even get a slap on the wrist.

As much as I like Rose, there's always a voice in the back of my head, when I watch Father's Day, that screams, "The world almost ended and you just press on, as if nothing happened?! REALLY?!"

If Suki is supposed a hard-as-nails freedom fighter, then why is she such a wuss when she reaches floor 500?

This one always cracks me up.
Doctor: Well Sergeant, aren't you going to say that it's bigger on the inside than it is on the outside - everybody else does.
Benton: That's pretty obvious isn't it?

OK, call me crazy, call me wrong but... it's not the worse even of the Troughton era. That will always belong to The Wheel in Space but yeah, it's pretty awful. Definitely in the bottom 15, if not 10, for me. In short: The Dominators are bullies, the Dulcians are wimps and nothing really happens.

So, let me get this straight: Electricity powers everything in the Dalek city, right? So, if they cut off the power, how did they get out of the city, considering they'd have to go through now-operative doors, lifts etc?

As the Doctor and Co. enter the house which leads to the maze, the creaking sound actually stops mid-way through and then re-starts later. As a result, the door is shut for at least 4 seconds before the creaks stops.

I've always loved Ace trying hard to keep a straight face, in episode 4, when she's yelling at Mike. She's supposed to be angry but you actually can see her smirking and looking like she might break into laughter, just before she dives out of frame.

She is really creepy and effective but it makes you wonder why Gilmore is so shocked when she leaves the chair. It's the exact size for a schoolgirl and, even he didn't put two and two together, hasn't he over thought of looking to see who it is?

And, for that matter, what does she leave so often, to observe people? And, for that matter, why is she even there, considering the Dalek Sec is always giving the orders and the Daleks' only emotion is hate? Why would they install a girl who goes against everything they've ever stood for?

And, considering she knows the Doctor's identity, why doesn't she blast him with lightning from her fingers and be done with it. He doesn't suspect her and she observes him several times? Ah, plot holes!

In two words: It's fine. It's nice and bright, with good lines and a creepy villain, but it feels a bit too... safe, maybe a bit rushed and Sarah Jane is ay to angsty, especially considering she's already returned to the screens twice. (I'm including K-9 and Company)

Vengeance on Varos
Because Sil the Mentor is in both.

This may sound SUPER nerdy but when I hear "tin man", I don't think of Wizard of Oz; I actually I think of the 3rd season Star Trek: Next Gen episode called "Tin Man."

You know, the one, right? The episode with the probe? That throws the Enterprise 3.8 billion kilometers away from it? And it's in the Romluan's sector? No? {Sigh} I feel so alone.

Carnival of Monsters, Warriors' Gate

OK, this isn't the worst but it's still stupid: The Mutants. There already was a story called The Mutants (although most of us call it The Daleks, nowadays, to avoid confusion) and they could really have thought of something more imaginative.

But, yes, Let's Kill Hitler is the worst name for one of the worst episodes. By the way, when I read thefifthdoctor's comment about "The Deadly Assassin", I just couldn't laughing, mainly because I couldn't believe I hadn't stopped and thought about that silly title.

The Invasion of Time

They both have departure scenes of female companions, because of romantic relations with a person not of their world.

The more I think about Nyki2's comment, the more I think he has a legitimate point and the more I realize my love of City of Death is taking over my life and decisions. OK, not really but a better cliffhanger and one I should have put down is when the alien steps out of the sarcophagus and kills Namin (Pyramid of Mars, Episode 1). Oh, and if you're wondering about that extra vote, I was scrolling down and accidentally clicked the Remembrance of the Daleks option.

Oh, boy. This one is overloaded with technical mistakes, plot holes, Hartnell flubbing just about every line (but when doesn't he?).
1: When Ian steps down from the pedestal, in The Screaming Jungle, a very loud off-camera cough is heard.
2: In The Velvet Web, Barbara says to Sabetha, "Your the one who put the disks on our foreheads." How on Marinus is supposed to know that, because A) She was asleep and B) When she woke up, she never saw the disk.
3: At the climax of episode 2, when Barbara is trying to destroy the Brain Creatures with the bar (or whatever it was), she only breaks one of the jars they are housed in.
4: One of the Voord, who is delivering Sabetha to Yartek, actually trips over his own flippers. 
5: If the only way to get around the island (and back the TARDIS) is the wrist watch/ travel dial, then why does Ian just hand it over to Vasor for a fur coat? Hello? Anyone?!

Um.. err.. uh. (really quickly) The Time Warrior... I think.