Easy to get them to stand up, because they have wide feet and bulky bodies. With GI Joes, Power Rangers, and action figures in general, I frequently have the figures falling over...and sometimes knocking over other figures in the process. I've even had some fall off of a shelf and land on the floor. That drives me crazy. I get all paranoid about something breaking or scratching. They won't stay still in some poses, and weapons or capes are often so heavy that it makes it impossible to keep the figures standing. Now, I know you can solve this with stands. I've actually bought a few, but I find that fix a bit annoying. I can put my Mega Man X or Optimus Prime in any position and they will stay in that position, no stands required. Even when I get other action figures to stand in the pose I want, typically after a certain number of days go by they fall over, as if gravity has been slowly working on them until finally pulling them down days after I posed them.
This may be one of the reasons some people prefer statues in static poses over action figures. Statues are built to stay standing, like this guy for example:

and they already come pre posed for your convenience
