She won't insult my bad Piggy when we sing "Love Led Us Here" or my terrible (I mean it!) Fozzie when we go over the "Good Grief! The Comedian's A Bear!" sketch from TMS.
The garage door at my house is really loud when it opens, and I've made it a tradition to practice my Red impersonation whenever it does...that way, I can make sure that none of the neighbors hear!
("Good grief - the comedian's a bear!")
When i was a kid i was fascinated with the Muppets pretty much right out of the womb. My best friend and i would play at being Jim Henson and Frank Oz the way other kids would play at being Cowboys & Indians. We would get all the toy hand puppets of all the characters (the hand puppets were such a huge part of the merchandise back then - it's sad we haven't really seen much of that since the 70's!) and were both determined to do them all so well so we could take over the characters when the real Muppeteers got too old! So i've been doing Muppet impressions a long time - i learned how to do a lot of different voices and a wide variety - which is easier for a child to do as puberty limits what one can do later! It was this early play that got me into puppetry (i was considered a prodigy at a young age and my first professional performing experience was as a puppeteer) and through puppetry i got into acting and singing.
At any rate, i pretty much hadn't done puppetry since my teens (the singing/acting eventually became the greater passion) and like i said, my range of impressions went down a bit after puberty though i could still do a large number (Frank Oz and Dave Goelz's - with the exception of Gonzo - being easiest) though as i got more into singing and developing my voice i tended to do impressions very little so as to not abuse or damage my voice - and when it turned out in 1999 that chronic bronchitis would be part of my life from then on, i've had to REALLY be careful and superprotective of my voice since then so the only time i even would do an impression nowadays would be if i was quoting a line and wanted to do so in character.
I never had a problem with Bert's laugh - heck i LOVE doing Bert (though i love - and usually will do - his mid 70's vocal patterns as opposed to more modern era) I also have always been big on voicespotting - again going back to that early obsession with Muppets, Muppeteers, impressions, voices, etc. And when Fraggle Rock debuted (and when i wasn't as sharp with voicespotting) i at first thought Jim was Traveling Matt and Frank was Boober.
Actually the one Muppet that i DO tend to impersonate these days just for fun and out of discovery is Wayne (and by extention Placido Flamingo) since i love the idea of a very vain singer and when just playing around on that on my own found out just how much i can sound like Wayne so every now and then when i can't resist (and my voice is up to it), i'll sing along to something as Wayne!