That is an awesome command that can only be obtained through God's supernatural love. If this very simple truth could be understood and applied, then strife would stop (Proverbs 13:10). The world would see Christianity as never before, and we would discover the true joy that comes from serving someone besides ourselves.
There is much confusion today on the subject of love because we have only one English word (love) to describe a broad aspect of meanings. [For example, if I said, "I love my spouse, I love apple pie, and I love my dog," obviously I am not talking about love in the same definition].
God's type of love; the highest kind of love, is when we seek the needs or good of others even when we don't feel like it. God's love does not come from feelings. Jesus displayed God's kind of love by going to the cross and dying for us even though He didn't feel like dying. Jesus wanted the best for you and me, regardless of His feelings.
We, can also love our enemies even though we don't have a warm feeling of affection for them. If they are hungry we can feed them; if they are thirsty we can give them a drink. We can choose to seek the needs and good of others regardless of how we feel.
If anyone becomes a servant and humbles himself with the motive of being praised, then he is not truly fulfilling Jesus' command. Jesus is teaching about a true, servant's heart, that loves others more than itself and will joyfully go without so that someone else may prosper.