The religious leaders asked Jesus what commandment was the greatest (trying to test Him). Jesus answered with part of the Shema: Love the Lord your God with all your heart, soul, and mind. He then stated that the second greatest commandment is "Love your neighbor as yourself."
Jesus showed that our love for God should be our top priority, but that loving others is also important. Love is vertical (with God) and also horizontal (to others). Yet He stated that we should love our neighbor which is not generic but specific. It is easy to say we love the world or a specific people-group, but to say we love people who are right down the road; people who may bother us or who act strangely is a unique challenge.
We should consider that only Jesus demonstrated perfect love with His life and ultimately the cross. His sacrifice shows that true love is about humility. And true love will require a sacrifice.
When we are tired and we lack the strength to love others, remember the experiences of Jesus of how He sacrificed His own life so that we can experience His love. Then we just reflect His love to others.