Chrone has pretty much given everything away, but there'd better be an answer tying it together. I am still pretty unsure of some of the details here.

The taste you were feeling the lack of was

butter.

In each of your frustrating incidents

you did, or expected, X but got butter-X which was not at all the same thing. (More or less. Sometimes you did X wanting butter-X but didn't get that. Sometimes the link is less clear.) Why all this would make you want butter, or arise from your wanting butter, isn't clear to me :-), but let's proceed.

You played soccer but absquatulated because you were insulted.

I guess they called you a butterball, meaning a fat person. Not sure why "absquatulated" is italicized here, but maybe it came to mind because of the -squat- in the middle.

Your cup of tea isn't the Amabuki sake.

Amabuki sell sake made with various different "flower yeasts". I can't actually find buttercup on their list, but I assume it's one of them.

You ordered sashimi but didn't get the agushi special you wanted.

I still don't understand this. There is such a thing as a butterfish but it doesn't seem to have anything to do with agushi.

You ordered a Macallan but got something too sweet.

You got butterscotch instead of scotch.

You ate some nuts but they were mixed with dried pumpkin.

You wanted nuts and got butternut squash (which isn't actually the same thing as pumpkin, but they're similar enough that you-in-the-story might have confused one for the other).

Your stoner friend forgot to water your plant.

He was too busy with his weed to tend to your butterweed.

I'm really just filling in details already sketched by Chrone in comments, so if you like this answer I suggest you go and upvote Astralbee's instead.

Chrone has pretty much given everything away, but there'd better be an answer tying it together. I am still pretty unsure of some of the details here.

The taste you were feeling the lack of was

butter.

In each of your frustrating incidents

there is some combination of X and butter-X (e.g., scotch and butterscotch), and having had, or had cause to think about, all those butter-X things made you feel that you needed butter too. (So, at least, I understand OP's comments after I expressed some confusion as to why these coincidences should make you want butter.)

You played soccer but absquatulated because you were insulted.

I remain rather confused by these. I wondered whether you were insulted by being called a butterball (soccer is called football rather than merely ball, but I guess one speaks of children "playing ball" for any number of different games, of which soccer would be one), but OP's comments suggest that that wasn't the idea. As for absquatulated, I guess it's not too far from meaning the same as "fly" -- but I don't see any butterflies in the text. There really ought to be a word beginning "butter" that's close in meaning to "absquatulate" and "insult", but I can't find one.

Your cup of tea isn't the Amabuki sake.

Amabuki sell sake made with various different "flower yeasts". I can't actually find buttercup on their list, but I assume it's one of them.

You ordered sashimi but didn't get the agushi special you wanted.

It seems like something rather indirect is going on here. Agushi means gourd seeds. There is a kind of fish that is sometimes called the "melon seed"; it is also called the Japanese butterfish. So you got ordinary Japanese fish instead. (This is the opposite way around from some of the other cases below: here you wanted butter-X but got X, but in the other cases you wanted X but got butter-X.)

You ordered a Macallan but got something too sweet.

You got butterscotch instead of scotch.

You ate some nuts but they were mixed with dried pumpkin.

You wanted nuts and got butternut squash (which isn't actually the same thing as pumpkin, but they're similar enough that you-in-the-story might have confused one for the other -- and OP informs me in comments that in some parts of the world they call it "butternut pumpkin", which I'd had no idea of).

Your stoner friend forgot to water your plant.

He was too busy with his weed to tend to your butterweed.

I'm really just filling in details already sketched by Chrone in comments, so if you like this answer I suggest you go and upvote Astralbee's instead.