Galatians 5:22-23 tells us what fruit it is we should be producing, but earlier in the chapter Paul gives us a list of the things that the flesh desires, which are opposite traits of what the Spirit creates within us. Let's take a look at both lists.
Flesh
"Now the works of the flesh are evident: sexual immorality, impurity, sensuality, idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, envy, drunkenness, orgies, and things like these. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God." Galatians 5:19-21
Spirit
"But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law." Galatians 5:22-23
Can you see the differences in how we should be living once we have the Spirit living within us? Without the Spirit we are still living for our own fleshly desires and the product of those desires is never anything good. Paul calls the characteristics that the Spirit produces fruit because fruit is grown naturally and when the Spirit resides in us His fruit is naturally produced too!