Learn Turkish: Bu trolleri görmezden gel, yoksa çok kızacaksın. - Ignore these trolls, otherwise you will get very angry.

It's a common idiom! It literally translates to "come from not seeing." It's formed by taking the negative aorist of görmek (to see), adding the ablative case -den (from), and combining it with gelmek (to come). By acting as if you didn't see something, you are ignoring it.

Why does trolleri have the -i ending?

The -i is the specific accusative case suffix. It is needed here because you are telling the person to ignore these specific trolls (bu troller). When a direct object is preceded by a demonstrative word like bu (this/these), it must take the accusative case.

I know yok means "there is not." How does yoksa mean "otherwise"?

Yoksa is formed by adding the conditional suffix -sa (if) to yok. Literally, it translates to "if there isn't." It serves as the standard conjunction for "otherwise" or "or else" (as in, "if you don't do this, then...").

Could I say kızgın olacaksın instead of kızacaksın?

While kızgın olacaksın literally translates to "you will be angry," native speakers strongly prefer using the verb kızmak (to get angry) for expressing this emotion. Kızacaksın is much more natural and common.