I like how this would be lore accurate. Patrick's first break up would be sad because he's never been in love. Plankton has been married for years, his anguish would turn into anger like a "how could you do this to me after all we've been through?"
Patrick has more of a feel like this was after his first relationship, which went wrong and scared him away from other relationships. Meanwhile, Plankton is irritated that Karen finally got tired of his schemes and left.
You must think that I'm stupid You must think that I'm a fool You must think that I'm new to this But I have seen this all before I'm never gonna let you close to me Even though you mean the most to me 'Cause every time I open up, it hurts So, I'm never gonna get too close to you Even when I mean the most to you In case you go and leave me in the dirt But every time you hurt me, the less that I cry And every time you leave me, the quicker these tears dry And every time you walk out, the less I love you Baby, we don't stand a chance, it's sad, but it's true I'm way too good at goodbyes (I'm way too good at goodbyes) I'm way too good at goodbyes (I'm way too good at goodbyes) I know you're thinking I'm heartless I know you're thinking I'm cold I'm just protecting my innocence I'm just protecting my soul I'm never gonna let you close to me Even though you mean the most to me 'Cause every time I open up, it hurts So, I'm never gonna get too close to you Even when I mean the most to you In case you go and leave me in the dirt But every time you hurt me, the less that I cry And every time you leave me, the quicker these tears dry And every time you walk out, the less I love you Baby, we don't stand a chance, it's sad, but it's true I'm way too good at goodbyes (I'm way too good at goodbyes) I'm way too good at goodbyes (I'm way too good at goodbyes) No way that you'll see me cry (No way that you'll see me cry) I'm way too good at goodbyes (I'm way too good at goodbyes) no No, no, no, no, no (I'm way too good at goodbyes) No, no, no, no No, no, no (I'm way too good at goodbyes) (No way that you'll see me cry) Ah-ah-ah (I'm way too good at goodbyes) 'Cause every time you hurt me, the less that I cry And every time you leave me, the quicker these tears dry And every time you walk out, the less I love you Baby, we don't stand a chance, it's sad, but it's true I'm way too good at goodbyes