Amisa pooja for Buddha

I know that we can make great Karma by offering Flowers,candles,incense,food,robes and other things for the Buddha statue thinking as if the Buddha is alive. But whenever I do offer these things my mind says "The Buddha is not there to receive this.And this is not the proper way to pay respect for the Buddha. The proper way is to try to be mindful and try to be free from the defilement in the mind." Am I cultivating bad thoughts by thinking this way? What is the proper way to think when we offer these things to the Buddha statue?