As they say, there are two rules in improv: Never say no, and never ask why. When another actor asks 'Why?' or says no to something you're suggesting, then it's very clear that they're putting the onus on you, because they're not comfortable with it themselves.
“Normally, the same strange impulse which brings a crowd to an accident is present in the reaction to a concert in which something goes wrong.”
“Even the 'Today' programme involves a balance between the worthy-but-heavy items with the worthless-but-entertainingly-light ones.”