Words beginning with you are limited to forms of you, youth and young. If you mean "Happy words beginning with a U sound," perhaps you refer to euphoric.
5 letter words beginning with g ending with L:grillgrowl
Gangstergangplankgoregalaxygumbogasgassygloriousglitzygrittygammagaudyglossygargantuangoon...are cool words.
positive words beggining with n
gnat, gnome
goat
ghostghoulgoblingoregrotesque
wonderful, whimsical, witty
beginning
Gnatssion
· Geranium · Gerbera Daisy · Gladiolus
happy time, humping, humming a tune out,