Happy wife, happy life ... so says UConn basketball coach Kevin Ollie who tells TMZ Sports the smartest guys in the NBA are the ones who let their wives call the shots. 

Ollie was out in D.C. on Monday ... and since he spent so many years playing in the NBA, we had to ask how the players decide where to vacation when the season ends. 

According to Ollie, it's not really up to the players ... it's up the person who's REALLY in charge -- their wives.