Too many convenient logistical details. As I recall:

The Gray Matter couple apparently don't subscribe to a security monitoring service.

Super-nervous Lydia owes her demise to being written as a repetitive cartoon character (and the bizarre Deus Ex Ricin).

Skyler's apartment has some weird pillar in the kitchen which allows for dramatic camera shifts.

The Neo-Nazis not only allow Walt to drive his car into their compound and park it how he wants, they don't check the gigantic trunk (bomb, maybe?).

Walt is hit only once in the machine gun barrage, lives to keep acting and finish the episode.

Todd and Jack survive, as well (but no one else), for a trite dramatic payoff.

Then to address the great revelation that Walt actually cooked meth because he enjoyed it, not for his family's benefit this really makes his getting so chewed up over Hank's death much more difficult to swallow; and the price he paid for his attachment to Jesse further makes no sense. Additionally, the Ricin should have been used much earlier... on Marie. Never once did I ever believe Walt was "evil," but rather purposely written to be as morally conflicted as possible.

All in all, if you think about it, this series was carefully constructed yet a nonsensical mess. If you only *feel* about it, it was probably great.
"The trouble with being a ghost writer or artist is that you must remain anonymous without credit.
If one wants the credit, one has to cease being a ghost and become a leader or innovator."
Bob Kane