Learn Hardcore German: Wir treffen uns an einem ruhigen Ort, damit jeder ein gutes Gefühl hat. - We are meeting at a quiet place so that everyone has a good feeling.

In German treffen can be reflexive (sich treffen) when you mean “to meet (each other).” The uns is the reflexive pronoun for wir (we). You can’t drop it because without it treffen alone usually means “to hit” or “to run into” someone. Word order also places the pronoun right after the finite verb in a main clause.

Why is it an einem ruhigen Ort instead of using the accusative case or another preposition?

Preposition meaning
- an
  - dative = location (“at a spot”).
- an
  - accusative = motion toward (“to a spot”).
    Here we’re staying put (“we meet at”), so it’s dative.
Dative article and adjective ending
- Masculine dative singular of ein becomes einem.
- After an article in dative, the adjective takes the weak ending -en, so ruhigen.
  Result: an einem ruhigen Ort.

Why is the verb hat placed at the end in damit jeder ein gutes Gefühl hat?

Because damit is a subordinating conjunction. In German subordinate clauses, the conjugated verb moves to the very end. Hence damit … hat.

Why do we use damit here, and could we use um … zu instead?

damit introduces a clause when the subject of the main clause (wir) is different from the subject of the subordinate clause (jeder).
um … zu requires the same subject in both parts and uses an infinitive construction (um ein gutes Gefühl zu haben).
Since wir ≠ jeder, you need damit
- finite verb.

Why do we say jeder takes hat and not alle with haben?

jeder means “each one” and is grammatically singular, so it pairs with hat.
alle means “all (together)” and would be plural, requiring haben.
Using jeder emphasizes that every individual feels good, not just the group as a whole.

Why does gutes have -es in ein gutes Gefühl?

Gefühl is neuter.
In the accusative case (direct object), neuter strong adjective endings after an indefinite article require -es.
That’s why gut → gutes with ein in ein gutes Gefühl.