To many people, minor chords sound sad, and major chords sound happy. The middle note of a minor chord is just a little bit lower than the middle note of a major chord, which is what makes this phenomenon possible. That being said, whether chords sound happy or sad depends on context.  For example, the song “Leviating” by Dua Lipa uses all minor chords, but it does not sound sad to most people.  Other factors, such as rhythms, instrumentation, and the notes used in the melody, have huge impacts on the emotions a piece of music can convey. NME has a great article about minor chords and keys, and the science behind the emotions they can summon.