Try being extremely happy at a slow pace. It doesn't work.
Tempo is integrally related to mood.
Some words have been adopted as standard measurements for tempo.
(beats per minute) Italian: English translation
(40-50) Grave: heavy, solemn
(47/8-54) Largo: wide, broad, generous
(54-62) Lento: slow, lose
60 Adaggio: slow, saying
62 Largetto: a little wide
(70-80) Andante: walking
(90-110) Moderato: moderately
(120-140) Allegro: happy and bright
(140-150) Allegro assai: very happy
(150-160) Allegro vivace: happy with spirit
(160-184) Vivace: spirited, bright
184 Presto: quickly, hurry up!