Smith says the switch has revived his love for the game.
"People might think I should have gone somewhere other than MK Dons but I had five months here last season and it relit my love for football," he told the Daily Mail.
"The decisions I've made have not always been the most popular but, when I look back, I want to know I've played for good football teams. An old friend from Leeds told me, "When you retire from football, no-one will say you were a nice person or a bad person, they'll just forget about you".
"You've got to make sure every decision you make is right for you as a person. If you think you can go to a better club than the one you're at, then, regardless of what anyone says, you should go."