Ah, that old chestnut.   Well, of course, strapping a couple of plastic Coke bottles to your back, putting a cardboard box on your head and pretending to be an astronaut is all very well and good - and in no way is it strange and unnatural - but it can have some nasty side effects.   The tendency to be involved in accidents is one of the main ones - as you have already discovered to your cost - but there are steps you can take to minimise the risks.   The most important is to ensure that you have cut eye holes into the cardboard box.   Real astronauts always have eye holes cut into the their cardboard boxes, as it helps prevent them from walking into the sides of rockets, tripping over moon rocks and falling into craters.  You would be well advised to follow the same policy.  If you already have holes cut into your box, ensure they are correctly aligned with your eyes - Wonky Box Syndrome is a common problem in space travel, and was a serious setback to NASA during some of the early Apollo missions.