I should have bought you flowers

From the "I should have  known better" by the Beatles  to    You should see me in a crown by Billie Eilish there are hundreds of songs where modal verbs are used and a great way for you to remember them.
Let's go romantic, oooooh a bit and listen to Bruno Mars

What does he regret?

Hold on a second! Is his English correct?  Can you find any mistake in the following lines?

Hmmm too young, too dumb to realize
That I should have bought you flowers and held your hand
Should have gave you all my hours when I had the chance
Take you to every party cause all you wanted to do was dance
Now my baby is dancing, but she's dancing with another man.

And others like Roxette sang "It must have been love"
Gloria Gaynor told herself she should have changed that stupid lock and she should have made him leave his key...
 More recently the fantastic Jamie Cullum  Kept repeating  Even though I might, even though I tried I can't  in the "Well you needen't"
and lots of examples could  be added if I had the time...

MORE ON MODALS
https://teachingenglishpalmira.blogspot.com/search?q=modals
https://teachingenglishpalmira.blogspot.com/search?q=MODAL+VERBS
https://teachingenglishpalmira.blogspot.com/2019/05/translation-modals-3-eso-bilingual.html