Commitment
Commitment
[Cueball proposing on his knee holding a box with a ring in it up to a girl with long blond hair. The text is written above them in a frame with yellow background.] I understand now. There's no choir of angels when you meet the right person. It's about growing out of your fears to realize what you have is what you want.
[Cueball and the woman are getting married. They stand under a gate of honor with a priest in front of them.] Girl: I do. Cueball: I do.
[Cueball walks hand in hand with blond girl when a cloud with trumpeting angels appears over Megan.] Megan: Hi.
[Same picture but without the cloud and angels. Cueball's thought is written in a frame with yellow background.] Well, shit.

In the first panel, Cueball proposes to a woman. While he does this, a narrator (most likely the man's inner voice) explains why he wants to marry her. It's implied that he had doubts about their relationship. He'd never experienced a moment of overwhelming love and certainty, especially when they met, which he describes as "a choir of trumpeting angels when you meet the right girl." He's come to believe that such a scenario is actually implausible, and a serious relationship is about "realizing that what you have is what you want."
In the second panel, they get married. And in the third panel, after they are married, Megan comes in saying 'Hi.' His wife appears to still be wearing her wedding veil, implying that he meets Megan immediately after the scenario.  Cueball has the full 'love at first sight'-experience, with a literal choir of trumpeting angels, suggesting that Megan is actually the one he's supposed to be with. That this realization strikes him immediately after he married someone else puts him in a very difficult situation. This is expressed by him thinking 'Well, shit.'
The title text notes that the previous guy who had a similar experience fell in love with one of the angels instead, not realizing that it was the girl he just met that was the love of his life. Which is of course much worse, especially because the angels are transient, and the only way to see them again is by meeting the perfect 'girl' and he has just ignored her! Alternatively, it could mean that that person was actually the last person to have such an experience, possibly because the persons succeeded in marrying and having children with the angel, resulting in offspring that were too powerful or otherwise undesirable. Something similar happens in Genesis 6:1–4, so this may be a reference to the Bible.
The humor of this comic plays upon a common anxiety in trying to build relationships. A person may be dating someone who they enjoy being with, but expect a moment of supernatural clarity announcing that they've found the right person to spend their life with. Most people never have such a moment, and have to build their relationships slowly, based on more prosaic considerations, like compatibility, commitment, and shared life goals. Frequently, people will build such a relationship, but worry that a magic and transcendent love is still out there, and if they 'settle' for the person they're with, they may find that love later and be unable to act on it.
The comic 584: Unsatisfied could be seen as a continuation of this - with the blond girl being depicted as Ponytail . It can also be seen as a deconstruction: in the subsequent comic, no matter which partner he chooses, he spends the rest of his life thinking about the other, apparently never being totally satisfied with the relationship he has.
[Cueball proposing on his knee holding a box with a ring in it up to a girl with long blond hair. The text is written above them in a frame with yellow background.] I understand now. There's no choir of angels when you meet the right person. It's about growing out of your fears to realize what you have is what you want.
[Cueball and the woman are getting married. They stand under a gate of honor with a priest in front of them.] Girl: I do. Cueball: I do.
[Cueball walks hand in hand with blond girl when a cloud with trumpeting angels appears over Megan.] Megan: Hi.
[Same picture but without the cloud and angels. Cueball's thought is written in a frame with yellow background.] Well, shit.
