Fast and Furious- like a car crashed into your brain

I'm still reeling from the barrage my brain took for watching the fourth installment of the Fast and Furious series. It doesn't get any more dumbed-down than this. This may be a long entry, so please bear with me.
Fast and Furious takes place five years after the events of the first film and Dominic Toretto (Vin Diesel) returns to his old stomping grounds to find the murderer of his girlfriend Letty. Meanwhile, Brian O'Conner has moved up in the FBI and is investigating a major drug cartel who are using street racers to transport their drugs. Anyways, after some silly plot developments the two cross paths once again.
Dumb development one: Dominic goes to the crash site where Letty was killed and is able to determine that the burn marks on the street are from a certain car nitrate that only one guy in LA sells. Coincidentally, this guy is still in the only one in LA who sells it and Dominic knows where this guy works. You'd think in five years something would have changed but no. Even more lame-brained is that the FBI couldn't figure this out themselves.
You know what? I can't even continue writing about how many silly things went down in this movie. I mean, it's a given that it would have a bad plot so I'll leave it there. Let me break down the other elements of the movie. There was no mise-en-scene worth talking about. The camera work was ok, but the editing was choppy and poor. The car races were hard to follow because like a lot of action movies these days constant cutting is used to create tension rather than good old fashioned filming techniques. The acting was funny, but I don't know if I should blame the director or actors. When Jordana Brewster, who plays Dominic's sister Mia, says, 'I love you.' it was like an, 'I'm in love with you.' Which is kinda....weird. Nitpicky, I know, but nonetheless bad. The dialogue was hilarious. How many movies has someone replied, 'Every day.' when being asked how often they think about a bad decision they made? Like, come on! We get that you're 'tortured'. Maybe something like, 'Too often.' would have been better. That's different at least! What else can I complain about? Oh yea, is it just me, or is it not hilarious when every character looks like the clothes they were came fresh out of the box? Hahaha, like, what? Just hilarious.
I'd like to say I'm done, and I will stop typing, but there is just too much that was bad about this movie not to keep going. I'm going to watch a really good movie soon so that it will be amazing in perspective and save some of my sanity.