Learn Icelandic: Mér hefur alltaf þótt kryddaði maturinn bestur. - I have always found the spicy food the best.

The verb þykja (to find or consider) is a quirky verb. It requires the person holding the opinion to be in the dative case. Therefore, the nominative ég (I) becomes the dative mér.

Since mér refers to 'I', why does the sentence use the third-person verb hefur instead of hef?

In Icelandic, quirky dative subjects do not control verb conjugation. Because mér is in the dative case, the auxiliary verb hafa defaults to the third-person singular form. That is why we see hefur instead of hef.

If the spicy food is the thing I have an opinion about, why is maturinn in the nominative case?

While a regular action verb takes an object in the accusative or dative case, verbs of opinion like þykja pair a dative experiencer with a nominative theme. The thing you are judging (maturinn) must always be in the nominative case.

Why does kryddaði end in an -i but bestur ends in -ur, when both describe the same masculine noun?

Kryddaði is a weak adjective because it directly modifies a definite noun (maturinn, the food). Bestur is a strong adjective because it acts as a predicate here, stating the conclusion about the food. Both are in the masculine nominative singular to match matur, but they use different declension patterns based on their grammatical role.