This is another one of those Elvis movies that lots of Elvis fans hate. But I like it. First: I'm a sucker for any movie with underwater scuba stuff. Second: The supporting cast is good. Especially Elsa Lanchester as the yoga lady and Frank McHugh as Captain Jack. Skip Ward is a typical '60s "pretty boy" heavy and Pat Priest makes a great femme fatale. Wow! What a figure! Wish Elvis would have ended up with her instead of the "virginal" Dodie Marshall.
Liked her better as the "new" drummer in "Spinout". But she was okay. Third: The soundtrack gets a bad rap. Why? "Easy Come, Easy Go"; You Gotta Stop; I'll Take Love";
"Sing, You Children" are all good. 'The Love Machine" is listenable. The only bad one is
"Yoga Is As Yoga Does". But in the context of the film with the visuals it's hilarious.
My advice? Watch it again. Go with the flow. You'll enjoy it.