Δεν μας συμφέρει να πάμε με ταξί τώρα, γιατί έχει πολλή κίνηση.

Here συμφέρει means something like is advantageous, is worth it, is in our interest, or makes sense practically.

So Δεν μας συμφέρει... is a very natural Greek way to say that something is not a good idea for us, often for reasons of money, time, convenience, or practicality.

It is not just about money. In this sentence, the reason is traffic, so the idea is closer to it’s not worth it for us to go by taxi now.

Μας means us / to us / for us.

With συμφέρει, Greek usually uses an object pronoun like this:

• μου συμφέρει = it suits me / it’s worth it for me
• σου συμφέρει = it suits you
• μας συμφέρει = it suits us / it’s worth it for us

So μας is not the subject. It shows who the situation is advantageous for.

Because μας is not the subject of the verb.

The verb stays in 3rd person singular because the whole action να πάμε με ταξί τώρα acts like the subject, or Greek treats it in an impersonal way, similar to English it in:

• It isn’t worth it to go by taxi now.

So Greek says:

• Δεν μας συμφέρει να πάμε...

Literally, this is close to:

• It is not advantageous for us to go...

After verbs like συμφέρει, Greek commonly uses a να-clause to express the action being talked about.

So:

• Δεν μας συμφέρει να πάμε... = It’s not worth it for us to go...

Here να introduces the subordinate clause, and πάμε is the verb inside that clause.

This is extremely common in Greek:

• Θέλω να πάω = I want to go
• Μπορούμε να φύγουμε = We can leave
• Δεν συμφέρει να περιμένεις = It’s not worth waiting

Here πάμε is the aorist subjunctive form of πηγαίνω / πάω after να.

Greek often uses the aorist subjunctive for a single, complete action:

• να πάμε = to go / for us to go

That fits this sentence, because it refers to one specific trip now, not a repeated or ongoing action.

If Greek used a present-type form, it would suggest something more ongoing, repeated, or habitual.

The form is the same, but the function is different.

• Πάμε! on its own can mean Let’s go!
• να πάμε after another verb is just part of a subordinate clause: to go / for us to go

So in this sentence, πάμε is not an imperative. It is simply the verb form required after να.

Με is the normal preposition for expressing means of transport in many cases, so:

• με ταξί = by taxi
• με λεωφορείο = by bus
• με τρένο = by train

So να πάμε με ταξί means to go by taxi.

Greek is focusing on the mode of transport, not on the act of hailing or taking one.

Because με ταξί is a general expression meaning by taxi.

When Greek talks about transport in a general way, the noun may appear without an article, especially in expressions like this.

You may also hear με το ταξί, but that can sound a bit more specific or concrete depending on context. In this sentence, με ταξί is very natural because the meaning is simply by taxi in general.

Literally, κίνηση means movement, but in everyday Greek έχει κίνηση is the normal way to say there is traffic or traffic is heavy.

So:

• έχει κίνηση = there is traffic
• έχει πολλή κίνηση = there is a lot of traffic / traffic is heavy

Grammatically, έχει is often used in spoken Greek almost like English there is / there are.

So this is a very idiomatic everyday expression.

Because πολλή has to agree with κίνηση, which is a feminine singular noun.

• πολλή = feminine singular
• πολύ = neuter singular or adverb

Since κίνηση is feminine, Greek uses:

• πολλή κίνηση

Compare:

• πολλή ζέστη = a lot of heat
• πολλή δουλειά = a lot of work
• πολύ νερό = a lot of water (νερό is neuter)
• τρέχει πολύ = he/she runs a lot (πολύ as an adverb)

Γιατί can mean both why and because.

You tell the difference from the context:

• In a question: Γιατί έφυγες; = Why did you leave?
• In a statement: Έφυγα γιατί κουράστηκα. = I left because I got tired.

In your sentence, it comes after a comma and introduces the reason, so it clearly means because:

• ..., γιατί έχει πολλή κίνηση.

Yes. Επειδή can also mean because.

So this would also work:

• Δεν μας συμφέρει να πάμε με ταξί τώρα, επειδή έχει πολλή κίνηση.

In many everyday contexts, γιατί is very common and natural. Επειδή can sound a bit more explicitly explanatory or slightly more formal, depending on context, but both are correct here.

Not completely. Greek word order is fairly flexible, although some parts are more fixed than others.

For example, these are possible:

• Δεν μας συμφέρει να πάμε με ταξί τώρα...
• Δεν μας συμφέρει τώρα να πάμε με ταξί...

Both are understandable. The difference is mainly one of emphasis.

What is less flexible is the placement of small words like δεν and μας:

• Δεν μας συμφέρει is the natural order.
• You generally would not move μας around freely.

So the sentence structure can shift a little, but the core grammar stays the same.