"Where it's thin, there it breaks"
Meaning:
That's what they say when failure occurs exactly where it was weak: in relationships, in plans, in character. It is not the enemy that fails, but man's own frailty. And always at the most inopportune moment.
where is the picture from?
Imagine an old bag: it looks intact, but where the fabric has become thin, it will burst at the first load. It's the same in life: if something is "thin", sooner or later it will crack.
A proverb is common sense in two lines. She does not condemn, but reminds: strengthen your weak points before you have to pick up the pieces.
Proverbs
๐ฟ Russian proverbs