Improv students are taught time and time again not to be negative or say "no" in a scene.
This confuses people because sometimes the scene calls for them to say, "No." So they're confused. What do they do then?
Then you have the people who think being argumentative is funny.
Both result in lousy improv that leads to improvisers not knowing how to move forward in scenes. They feel stuck not knowing where to go.
First, let's sort out the confusion about what the note to not say, "no."
What Does it Mean to Not Say, "No?"
What instructors mean is to not negate what was given. For instance if someone says "Let's go to the park" and you were to say, "No," now you have to come up with a place to go and it prolongs the scene from going anywhere. You had a place you could have gone, but you rejected it. It just slows the scene down.
It's not that you can't or shouldn't say the word "no." You can, because people use that word in real life, but don't negate where the scene is heading.
Of course there are nuances to this. Sometimes your scene partner needs you to say, "no," to what they say. Most of the time, though, if an improviser says, "Let's go do this," or "Sure is great being a farmer," they aren't asking you to keep that from being what you do or what you are. They want you to say, "Yes, and..."
Not moving forward in the trajectory the scene is going just needlessly slows the scene down.
What Can You Do?
Say, "Yes, and...!" It's the bedrock principle of improv and I talk about in this blog.
What problems does saying, "no," really cause anyway? I'm glad I fake-asked myself that. I'd say there are a couple of things I commonly notice as a bad result of improv negating. Knowing what they are may help you to avoid saying, "no," in scenes and help you to "Yes, and," even better!
A Couple of Things to Avoid
Neutrality Sometimes people who don't understand the distinction start to improvise in a neutral way. There's no Anding but they're not saying no either. Nor are they remotely invested in their character or the scene. The scene is as vanilla as possible. "No mistakes made here cause I didn't make any real choice to begin with!" No harm no foul. Only...it's not good improv. It's arguably not improv because They're not collaborating. These improvisers end up standing around while their partners make all the choices that they barely acknowledge happen.
Negativity Some people who misunderstand the right way to say, "no," turn scenes into arguments right off the bat. This doesn't help because no one knows why the argument is happening. Not the improvisers or the audience. The improvisers have a hard time knowing why they are arguing and it's uncomfortable for the audience. Then there's plane ol' being negative in scenes. An improviser isn't saying, "no," but an their character is real critical of the other person(s) in the scene. They are not truly making any choices. Don't assume that this person does this because they're bad at improv. They very likely are so negative in scenes because they are a negative and/or judgmental person. Think about it. Improvisers are making choices based on the first thing that comes to mind.. Why would a negative thought be the first thing to come to mind? They either negative/judgmental by nature or they are down in the dumps. Sorting this out just may make you a happier person.