Forewarned is forearmed

If you know about something beforehand, you can prepare for it, prior knowledge of possible dangers or problems gives one a tactical advantage. Un homme averti en vaut deux

To click with someone

to catch on with someone. - le courant est passé avec quelqu'un

1. [for something] to be understood or comprehended by someone suddenly. 

• His explanation clicked with Maggie at once. It rings the bell.

2. [for someone or something new] to catch on with someone; to become popular or friendly with someone very quickly.

• The new product clicked with consumers and was an instant success. 
• I clicked with Tom the moment I met him.