Cleanliness and Perfection

So I recently stopped by at my sister-in-law's house and I only gave her like 5 minutes warning (I don't usually do this, but I had mentioned that I would be coming 2 weeks prior). Anyway, my sister-in-law recently had her 3rd baby, and so life is a little crazy for her, and when I called she told me that her house was a mess...and I said no problem (after all I realize that she just had a baby and I remember what my house was like after I had just had my baby). So when I got there, instead of sitting down and visiting, she was running around her house picking up little things (and honestly if she hadn't of said anything I really wouldn't have noticed). It got me thinking though, I do the same thing all the time...I know someone is coming over so I try to make my house spotless and if it isn't by the time they make it over than I am so embarrassed. So I guess my point is why do we try so hard to be perfect even when we are not? I know that our purpose in life is to strive for perfection, but why are we so scared to let our true selves show. I wonder if we were to let our true selves show if people could help us with our weaknesses and we would all become better. I probably will still clean my house every time I know someone is coming over (because let's face it, I just might not get it clean if I didn't), but maybe I will strive to not worry about it if it isn't perfect, because I'm not perfect.