We have adopted two stray cats, Gary and Little Foo. They sleep a lot and I have been able to teach Gary only one trick. From those experiences, I have adopted and adapted two proverbs:
Let sleeping cats lie.
You can’t teach an old cat new tricks. I have taught Gary to roll over and play dead. My wife says that he just wants his tummy scratched, but I claim that I taught him the trick. Gary has taught himself a trick that amazes passers-by; he frequently accompanies us on walks.