..., a cieszy! ;)
Why is "small thing" wrong? All I did was omit the "a"
is "rzecz" feminine?
Yes, indeed it is.
Can this also be used to say "a small issue" ?
No, I don't think so. Not without any context, at least. You can say "A, jeszcze jedna rzecz" (Oh, just one more thing) and maybe English could use "issue" instead of "thing"... but still, "thing" is the first thought, I think.
Реч (rech) in Ukrainian :D
someone apparently has a hobby here :D