What's Your Go-To Exercise?

I saw this thought oh this is easy it's just 6 easy excersise how wrong was I. No matter how fit I get this never gets easy talk about go to excersise for when you need that big calorie burn. I can still see where I improve on it I can jog in place at the 1"active rest bit till I start the 60 minutes one. Anyone else do a workout they though would be easy and it turns out to be anything but easy in a good way