grammar - Do you say "I like apple" or "I like apples"?

When stating a general fact/preference on countable nouns, singular or plural is more suitable and natural?

Example 1 :

I like apple.

or

I like apples.

Example 2:

I like eating apple.

or

I like eating apples.

Answer

Compare

"I like apples", means you like eating apples generally.

and

"I like the apple" means you are focused on one particular apple and you like this apple. Maybe you just like its shape and color.

However,

"I like eating the apple" means you are currently in the process of eating a particular apple and you like eating namely this particular apple or, which is most unlikely and funny you eat a particular apple from time to time (you like eating this apple)

As you can see articles are important here, you missed them in a couple of places of your questions, in: I like apple. and I like eating apple.

In some cases it's context that determines countability, not the word itself. You can meet tricky examples with apple like these:

"I like eating many fruits, but my favorite of all is the apple." (In that sentence, I'm not talking about any particular apple, but the genus of apple as a whole)

"There's too much apple in this fruit salad"

In some case a word can be both countable and uncountable, like when it can mean category or subject as in the next example:

"I bought a basket full of fruit." (perhaps one kind of fruit, perhaps not)

"I bought a basket full of fruits." (various kinds of fruit)