watch much stuff?

I do not see any problem with the grammar, but using "stuff" in this sense (I am guessing it means television programs, or something like that) is both vague and slangy. Perhaps it is that which is making you uneasy. Also, it is not a very euphonious sentence.

Yes, directly replacing programs on television (sorry for leaving that out).
I suppose it probably is the complete lack of euphony that is bugging me.

I think in the English language we have come to relate the word "stuff" with tangible personal property. Because you are trying to relate it with television programming instead, perhaps it is giving you a 'bad English' reflex?

I think nigel is right ... It is the vagueness of "stuff" in this sentence. What "stuff" are yu talking about? In context it becomes clearer if yu say: I don't watch much stuff like that (maybe talking about a TV program or a genre of film).

The grammar is ok. It's only out of context and thus is vague.

I think my problem may be 'much' being coupled with a plural noun (stuff in this case referring to 'tv shows'), in which case my brain is expecting 'many'. Obviously you wouldn't say 'many stuff', but I think that I'm still thinking of 'stuff' as 'shows' in my mind. Does that make sense?

"Stuff" is like "sugar." You don't have to say you have many sugar. You have much sugar. I believe it's called a collective noun. Other examples: material, money, water.

See, that sounds weird also. 'Much sugar'; 'much water'... It sounds odd to hear 'much' by itself I suppose. If it were 'very much' or 'that much'. My default would be to say 'I have a lot of sugar' instead of 'I have much sugar'. Heck, I could even tolerate 'I don't have much sugar'. So once again, it boils down to '[verb] + much', and it must just be the lack of euphony for my auditory palate.

I'd just say "I don't watch a lot of things".
Could that work as good?

/non-native English speaker

“Benjymyn
.......
Could that work as good?
/non-native English speaker”

So it seems.

"Stuff" is neither a plural noun, like "things", nor a collective noun, like "group" or "pack". Stuff, sugar, metal etc are uncountable (or non-count) nouns. As others have said, "many" is used with countable, while "much" is used with uncountable, but for both we usually prefer "a lot of" in positive statements, especially in informal English - "I watch a lot of stuff". But as Benjymyn suggested, it could work equally as well for the negative version. Otherwise I go along with the idea that it's a bit vague, although I wouldn't call it slangy; it all depends on context. But I don't think there's anything 'improper' about it.

@Hacovo - Are you sure people are saying "I don't watch much stuff" without further qualification? For example, if somebody said - "I don't watch much of the stuff that's on TV nowadays" - that would sound like an entirely natural sentence to me. Could you perhaps give us some more context, or better still, an example.

"I have much respect for Elena" works fine for me.