There will always be a lost dog somewhere that will prevent me being happy.

[Il y aura toujours un chien perdu quelque part qui m’empêchera d’être heureux.]

Jean Anouilh (1910-1987) French dramatist

La Sauvage [The Restless Heart], Act 3 [Thérèse] (1934) [tr. Pronko (1961)]
    (Source)

Alternate translation:

There will always be a stray dog somewhere in the world who'll stop me being happy.
[tr. Hill (1957)]