Learn Russian: Я не люблю пробки из-за шума. - I do not like traffic jams because of the noise.

Потому что means "because" and connects two full clauses with verbs (like "because it is noisy"). Из-за is a preposition meaning "because of", so it must be followed directly by a noun or pronoun. Here, it is followed by the noun шума (noise).

Why is шума in the Genitive case?

The preposition из-за always requires the noun that follows it to be in the Genitive case. Since the dictionary form is шум (a masculine noun ending in a consonant), we add -а to make it шума.

Does из-за always imply something negative?

Yes, usually. It is used for negative causes, excuses, or obstacles. If the cause is positive (like "thanks to the good weather"), you would use благодаря followed by the Dative case instead. Since noise is unpleasant, из-за is the right choice here.

Why does пробки look like it's in the Nominative case if it is the object of "I don't like"?

It is actually in the Accusative plural because it's the direct object of не люблю. However, for inanimate nouns (non-living things), the Accusative plural form is identical to the Nominative plural. By the way, пробка literally means "cork," which is exactly what a traffic jam feels like!