basu ga nakanaka konakute, sukosi irairasite simatta.

Both are possible in some contexts, but they give slightly different nuances.

• バスが来なくて focuses on the bus as the thing that did not come.
• バスは来なくて would feel more contrastive, like as for the bus, it didn’t come (maybe implying something else did, or contrasting it with another topic).

In this sentence, が sounds natural because the bus is simply the thing causing the situation.

In this sentence, なかなか means something like:

• not easily
• not readily
• not for a long time
• just wouldn’t

With a negative verb, it often expresses that something is taking longer than expected or is harder than expected.

So:

• バスがなかなか来ない = The bus doesn’t come / isn’t coming for quite a while

It often carries a feeling of impatience or frustration in this kind of sentence.

This is one of the most common patterns with なかなか.

Very often:

• なかなか + negative

means not easily, not readily, or not for a long time.

Examples:

• なかなか分からない = I just can’t understand it
• なかなか寝られない = I can’t fall asleep easily
• なかなか来ない = it doesn’t come / isn’t coming for a while

So なかなか来なくて is a very natural pattern.

来なくて is the negative te-form of 来る.

Here is the breakdown:

• dictionary form: 来る
• negative plain form: 来ない
• negative te-form: 来なくて

This 〜なくて form can connect to what follows and often means:

• because it didn’t...
• and it didn’t...

In this sentence, it connects the cause to the result:

• The bus didn’t come for a while, and/because of that, I got a little irritated.

It can suggest both connection and cause, but here it is most naturally understood as a reason/cause:

• Because the bus wasn’t coming, I got a little irritated.

Japanese often leaves this kind of relationship slightly implicit. The 〜て / 〜なくて form commonly links events where the first part is the reason for the second.

So in this sentence, the causal reading is the most natural one.

Because いらいらする is being put into te-form to connect with しまった.

Breakdown:

• いらいらする = to feel irritated / to get irritated
• いらいらして = te-form
• いらいらしてしまった = ended up getting irritated / got irritated unfortunately

So the main predicate is really:

• いらいらしてしまった

not just いらいらした.

いらいら is an onomatopoeic/mimetic expression that describes an irritated, frustrated mental state.

It usually appears with する:

• いらいらする = to feel irritated / to be irritated

This is very common in Japanese. Many feeling/state words work like this:

• どきどきする = to feel one’s heart pounding
• わくわくする = to feel excited
• いらいらする = to feel irritated

So いらいらしてしまった literally contains that する verb.

〜てしまった often adds one of these nuances:

• something was completed
• something happened unintentionally
• something happened regrettably
• the speaker feels oops, unfortunately, or I ended up...

Here, いらいらしてしまった suggests:

• I ended up getting irritated
• I got irritated without really wanting to
• Unfortunately, I became a little irritated

So しまった adds emotional nuance. It is not just a neutral past tense.

少し means a little or slightly, and it modifies the degree of irritation.

So:

• 少しいらいらしてしまった = I ended up getting a little irritated

It softens the statement. The speaker is not saying they became extremely angry, just somewhat irritated.

Yes. Japanese often omits subjects when they are understood from context.

The sentence does not explicitly say:

• 私は
• 僕は
• 彼は, etc.

But because the second half is about an emotional reaction (got irritated), it is usually understood that the speaker is talking about themself, unless context says otherwise.

So in natural translation, I is often supplied:

• The bus took forever to come, and I got a little irritated.

Yes. It is in plain form, so it sounds casual or neutral-informal.

Key points:

• 来なくて
• しまった

There is no です / ます style here.

A more polite version might be something like:

• バスがなかなか来なくて、少しいらいらしてしまいました。

So the original is natural in everyday speech or casual writing.

Not exactly, though the idea is similar.

• バスが遅れた = the bus was delayed / ran late
• バスがなかなか来なかった = the bus just didn’t come for a long time

The original sentence focuses more on the speaker’s experience of waiting and feeling frustrated, rather than explicitly stating the technical fact that the bus was delayed.

So it feels more like:

• The bus took forever to come

than simply:

• The bus was late

The final verb is しまった, which is past tense, so the whole sentence describes a completed event in the past.

That means:

• the bus didn’t come for a while
• as a result, the speaker became irritated

If it were non-past, it would describe a present/future situation instead.

So this sentence is talking about something that already happened.