The room would lack character or personality. Nothing in the room would relate to them personally. Yes, the room looks good, but if you are not represented in some way the place begins to feel cold.
Luckily this is the simplest thing to fix. I love to go to antique stores, thrift stores, and flea markets just to find those one-of-a-kind things that only my home will have. No need to spend much money, these things can be quirky, whimsical, funky or down right odd. Items your children have made for you would also work. All that matters is that it catches your eye and makes you smile.
Some of my items that have "Charm" or "Character"
Hay Rake (came from my grandmother's garage-love the simplicity of the design)
Ash Tray (we do not smoke-but it came from my grandmother's home and it's AQUA! my favorite color)
Sofa Piece? (this is what's left of a vintage love seat I purchased years ago-dry rot had ruined most of it, but we salvaged the parts we could)
Apple Peeler (I don't use it to peal apples, but it looks great on my Hoosier)
My Children's paintings (I love these!!)
Old Shutters (these came from my inlaws neighbor-love the color and patina)
Items from our travels
Inexpensive items from flea markets and junk stores.
These are the items that make the difference and give our homes personality.