The reason to have kids...

According to Kevin, the reason you have kids is to antagonize them.  He has been putting the bath decals on Indy's back because Indy keeps looking behind him to try and find what is on his back.  Of course he cannot locate them but he never gives up.  Kevin has been slowly working up to multiple decals on his head and he finally accomplished four!

Indy didn't seem to mind.  He won't wear a hat outside but you can stick bath toys to him and he could care less!