Sometimes the things that fall through are a blessing in disguise and you find something even better,

A blessing in disguise,

Remember, sometimes something might seem like bad news, but it could turn out to be a blessing in disguise.

This might be a blessing in disguise, believe it or not.

What I'm looking for is a blessing that's not in disguise.

[Or it's just a compulsion.] It's not something you choose to do, ... You can't avoid doing it.