A million ways
In improv, there are no shoulds, only coulds.
We all know this feeling after a scene or a show. "Oh! I should have done this!" and "Damnit, I should have said that!" are thoughts that have plagued many an improvisers mind, sometimes for long stretches of time after a play.
Unfortunately, there is a far worse variant out there too: "Oh! You should have done this!" or "Damnit, you should have said that!". People saying or thinking this haven't understood much of the improv mindset, in my opinion.
Every scene can go a million ways. Sure, something else could have happened, but would that difference have made it a nicer scene, a more compelling story, a better joke? It doesn't matter how long you think or talk about it, you will never know.
Do you know this traditional game where you drop a ball or disc along a plank with hundreds of nails through it to have it come out on the other side in a random position? Every time the disc bounces of a nail represents something that happenes in the scene. Removing or adding a single nail of course can have a big impact on the trajectory of the disc, but the outcome will still be unpredictable.
Bottom line: don't worry about what happened, and definitely don't complain about it.