1) Awkward Moments. There are times in my life where I have not been stellar. Memories I'd rather forget, and yet, your movie has some idiot saying or doing something that makes me embarrassed for them, which in turn churns up nausea-inducing flashbacks to high school/crowds/parties/girls/hazing. Trust me, you don't want me feeling queasy about your movie.
So stop it with the awkward speech, awkward confession, awkward meet-up, awkward sex, awkward-whatever-is-in-your-twisted-past-that-you-thought-looked-super-on-film.
2) Groups of Friends that Don't Look Like Friends. "Hey, we are all friends! We sit around and drink at nondescript bars and don't have real conversations, and we have nothing in common whatsoever! Let's move on to the plot!"
I hate your characters if they are comprised of six stereotypes that shouldn't belong. A protagonist, a stud, a geek, a slut, a wallflower, and a prude do not mystically group up for no reason. Give them a common purpose for being together. Pick something, anything. Make them all like kayaking, I don't give a shit. Just please don't make it any easier for me to not give a damn about your characters.
3) Invincible Normal People. If a non-superhero gets shot, punched, kicked in the face, thrown off a building, flung out of a moving vehicle, or whatever idiotic thing you think looks cool, please have them react accordingly. I've watched enough Mythbusters to know that Buster the crash test dummy is royally fucked over by one quarter the damage done to movie characters.
Yet, in Transformers 2, three normal humans in a car are dropped from the sky, a fall of about ten stories, and they are perfectly fine because of the airbags (even the dude in the backseat!) In Iron Man, Tony Stark gets flung about 100 yards in the desert, and he's fine because he's inside a steel suit he made in a cave. Sure.
So please, if your protagonist must be punched in the jaw, please break it, and have them be in agony for the next couple weeks. Your script will be greater because of it, I promise.
4) People Meeting Each Other. "Hi. Hi. I'm Jub Jub Binky. I'm Goo Goo Montana. I like peanuts. So do I. Do you like penguins? No. Me neither. Okay. Okay. Let's have a scene with conflict now. Sure, let's do that."
Cut out the beginning of every scene where people are meeting each other for the first time. I'm a smart dude. I can fill in the blanks. If you want two people to meet, do this: a) show the two people for 3 seconds. b) cut to them having a conflict. We can figure out that they met and did stuff before that point, and will be grateful that we didn't have to watch the tedious parts. Give us conflict now, not later, because by the time it gets to later, we will be too bored to care about your dumbass characters.
5) People Drinking/Eating. I realize that your actors are not talented enough to hold the audience's attention without a prop, so I understand your need to fill their hands with generic alcoholic drinks. However, might I suggest that you give these actions some characterization? Boring choices make your characters (guess what?) boring.
At the beginning of Chaos Theory, the so-called random Mom (who is pissed off that her husband is so bland), makes waffles, sausage and bacon. What, you thought I wouldn't notice? Movies are for watching, derp! Random Mom should serve leftover Chinese food and Pop Tarts for breakfast. Those would be memorable choices, and give the characters something to react to and argue over. Bing! Conflict!
Now I'm not saying every meal has to be filled with random crap. Just please please please please fit the choices on screen to who the characters are. Random Mom would not have a clean counter either, or a bowl filled with glorious fruit. She'd have clutter everywhere, and the sink would be filled with dirty dishes. Random Mom is a mess, so show her that way. We notice, and so should you.
6) Horrible Extras. In Hellboy 2, there is a scene in an underground troll market, with lots of despicable faerie creatures running around. Or actually it isn't, since there are only a couple of CGI monsters, while the rest of the crowd is made up of extras in robes with bags on their heads. We could have had a super cool backdrop, instead, what we got was Hellboy walking around a bunch of people with shitty costumes.
I get why you are doing this. If you make your extras look marvelous, then there is the chance that they might upstage your main characters, and we'll pay more attention to the background than the foreground. However, that just means your main characters are boring. Make everything exciting, and we'll be excited about your movie. Your movie is only as good as the weakest link, and if your weakest link sucks, then your movie sucks. Funny how that works.