Just as in English we do not say "more good" or "more bad," Italian has irregular comparatives for these common adjectives.
Better and Worse (Migliore and Peggiore)
To say "better" or "worse," use the irregular adjectives migliore and peggiore. Because they end in -e, they use the exact same form for both masculine and feminine singular nouns.
In Italian, "best" and "worst" are formed simply by pairing these words with a definite article (il, la, i, le). Depending on the context, la migliore can mean "the better one" or "the best one."
Excellent and Terrible (Ottimo and Pessimo)
While you can use the -issimo suffix you learned previously to form buonissimo (very good), Italian has special, highly frequent words for the absolute extremes of good and bad: ottimo (excellent) and pessimo (terrible).
These function just like normal adjectives ending in -o. They must change their endings to match the gender and number of the noun they describe (-o, -a, -i, -e).
Evaluating Outcomes
You will frequently use these extreme adjectives and comparatives to evaluate choices, customer experiences, and results. A very common phrase pattern in Italian is placing possibile (possible) immediately after the noun and comparative to evaluate an outcome.