When William Frawley (Fred) sees Lucy in the dress she makes, his reaction is so hysterical that it tickles Vivian Vance (Ethel) and Ricky, too. She tells the boys "We can't let her see us like this" when Lucy runs to check her perm to make up for the laughing. You can see Desi compose himself because he knows what she's going to look like when she comes back out. William Frawley looks like he's struggling to keep from cracking up for most of the rest of the scene.
Lucy is dying to get new furniture in this episode as hers is so ratty, but only a few episodes earlier she won a whole house full of new furniture in the episode "Redecorating".
While Lucy could have made small cuts in the carpet while using the razor blade, it would be nearly impossible to cut deep enough accidentally to cut through the carpet.
Lucy: Butter? On bread?
Lucy: I'll never get used to your strange Cuban dishes.
Lucy: (on her homemade dress) I made it with my own two hands!
Ethel: It looks like you made it with your own two feet!