to me, most of the time it does add a slight derogatory slant.
Frankly, I have not idea about the usage stats, but you are right. The -ucha ending tends to point to something rather derogatory (dziewczyna - dziewucha
) but, like with real estate, it's all about location, location, location i.e. context:
(if I don't like parsley, looking into a bowl of soup): Znowu pietrucha
!/Damn it, parsley again!
(shopping on the produce department) Ale pietrucha!/What a big parsley (root)!
Not derogatory among friends:
Zadzwonie do Darucha
(I'll call Darek) could indicate a degree of intimacy/friendliness.
I think you meant parsley
oopsie, you're right
would you not use 'its abig carrot instead of the ucha ending, so as maybe not to oddend anyone.
Not sure it works like that.
Sometimes you do want to offend. Sometimes you want to use a certain style and not offend. I guess this particular topic is pretty hectic and somewhat peripheral (as in not so critical) and not all nouns would lend themselves to its application. The usage of -ucha may as well be one of the best tests of the speaker's fluency in Polish :)