It depends heavily on the wish, honestly.
No wish is explicitly forbidden, in such a manner as to be forbidden from the word "go". But some wishes require such a massive investment of magical energy, or would cause such monumental havoc to the universe, that genies really don't like to grant them.
If you wish for such a thing from an experienced genie, you're going to get either A) A pretty thorough and patient explanation as to why that's a bad idea, or B) Get your wish seriously twisted, depending on what the genie feels about you.
Also, genies can sense your deepest desire - and the true motivation - behind every wish. They're on the hook for granting that, rather than the explicit word-for-word spoken wish that comes out of your mouth.
So if you, say, wish for the entire universe to collapse into a singularity, from which it can never be recovered, that all of creation be blighted into oblivion in the blink of an eye - she might just give you a really soft hug, a cup of tea, and lend an ear to your problems. Because maybe you just really need a friend in that moment.
Genies can also sense when the intent behind a wish is, simply put, vile. So if someone gets a hold of a bottle and makes some damned fool regressive wish, you can bet that one is getting turned around on them ASAP.
Of course, a lot of these considerations are nuanced and conditional. When you're fresh out of the lamp and going through introductions, sometimes it's just a lot easier to say "These wishes are off limits" than say "TECHNICALLY these wishes are within my power, but due to a number of reasons related to conservation of energy and causality, they are ill-advised". A whiff of deception, perhaps, but it keeps things moving along without getting too far into the weeds. Most people holding a genie botle don't care about the hoes or whys of genie-ness. They just really want their wishes. So a bit of polish on the delivery, and this method keeps everyone happy.
(Oh, and wishing for infinite wishes is, and always will be, a one-way ticket to geniefication. You set us up that blatantly? Yeah, we're gonna act on it.)