An effective warmup ultimately comes down to whether people engage those warmups with commitment. Often the reason players aren’t ready to go after a warmup isn’t necessarily because the warmup sucked, but people’s commitment to the warmup sucked, or their commitment in general sucks. That’s not necessarily going to change if you do a better warmup. Often, the warmup doesn’t need to get better. The attitude and approach needs to get better.
For me, it’s playing a crazy warmup that gets me warm for a show – something fun, something fast, something that’s easy to generate energy. I’m Coming Over For Pancakes, Vroom/Click/Clap, Rotating Pattern Game with four or more patterns are all great. Running half-assed intentionally bad scenes makes me to do bad scenes in shows.