We live in a culture that idolizes happiness. We act and believe as if our own personal happiness is the most important thing in life. Quotes like the following abound on the interwebs.
Then Jesus said to his disciples, “Whoever wants to be my disciple must deny themselves and take up their cross and follow me."
Denying myself is basically the opposite of pursuing the things that make me happy, unless, of course, Jesus is what makes me happy. (Perhaps you see where I’m going with this.)
The problem with a quote like “Respect yourself enough to walk away from anything that no longer serves you, grows you or makes you happy” is that it promotes the self-centered idea that life is all about me. It’s not, especially for Christians. Consider what the Apostle Paul wrote to the Christians at Philippi.
Do nothing out of selfish ambition or vain conceit. Rather, in humility value others above yourselves, not looking to your own interests but each of you to the interests of the others. In your relationships with one another, have the same mindset as Christ Jesus: Who, being in very nature God, did not consider equality with God something to be used to his own advantage; rather, he made himself nothing by taking the very nature of a servant, being made in human likeness. And being found in appearance as a man, he humbled himself by becoming obedient to death—even death on a cross!
As Christians, we are to become more like Jesus Christ. Jesus chose not to seek his own will (John 6:38). Jesus did not come to be served, but to serve (Mark 10:45). Jesus focused more on the well-being of others than he did on his own well-being; he was willing to suffer so that others might have life. This sounds nothing like being willing to walk away from things that didn't serve him or make him happy.
What about leaving whatever makes you feel bad and keeping whatever makes you smile? Consider Paul's words to the church at Corinth.
2 Corinthians 7:8-10
Even if I caused you sorrow by my letter, I do not regret it. Though I did regret it—I see that my letter hurt you, but only for a little while— yet now I am happy, not because you were made sorry, but because your sorrow led you to repentance. For you became sorrowful as God intended and so were not harmed in any way by us. Godly sorrow brings repentance that leads to salvation and leaves no regret, but worldly sorrow brings death.
Or how about the following quote from the writer of Hebrews?
...God disciplines us for our good, in order that we may share in his holiness. No discipline seems pleasant at the time, but painful. Later on, however, it produces a harvest of righteousness and peace for those who have been trained by it.
The truth is, not everything that makes us feel bad is bad for us, and not everything that makes us smile is good for us.
Finally, what about the idea that we should just let everybody do what makes them happy and mind our own business? What if the thing that makes me happy is harmful? Not everything that makes me "happy" is good for me (like fried food). Not everything that is good for me makes me happy (like salad). Consider parenting. (I'm not yet a parent, but I did have parents). I believe my parents wanted the best for me and in order to help me be my best sometimes they withheld things from me that may have made me happy in the short run (like ice cream for breakfast) and they made me do things that didn't make me happy (like clean my room). The point is, if we really love someone, sometimes we have to encourage them to stop doing things that may make them happy (or do things that won't) so they can have what's best for them in the long run. That's what God does for us. God may ask us to give up things in this life that may make us "happy" because he knows what's best for us overall. Consider the interaction Jesus had with the rich young ruler.
As Jesus started on his way, a man ran up to him and fell on his knees before him. “Good teacher,” he asked, “what must I do to inherit eternal life?” “Why do you call me good?” Jesus answered. “No one is good—except God alone. You know the commandments: ‘You shall not murder, you shall not commit adultery, you shall not steal, you shall not give false testimony, you shall not defraud, honor your father and mother.’”
“Teacher,” he declared, “all these I have kept since I was a boy.”
Jesus looked at him and loved him. “One thing you lack,” he said. “Go, sell everything you have and give to the poor, and you will have treasure in heaven. Then come, follow me.”
At this the man’s face fell. He went away sad, because he had great wealth.
Clearly, for this man, following Jesus meant doing something that didn't make him happy. Jesus knew that this man's riches, which made him happy, were actually an obstacle preventing him from finding eternal life. Jesus asked him to give up something that made him happy in this life so that he could find eternal life.
Please don't read what I'm not writing. I'm not saying that being a Christian means that we have to give up on happiness and live a miserable life. What I am saying is that instead of pursuing happiness, pursue God and trust that God, as a perfect father, has your best interests at heart. When you do, you will find joy unspeakable in this life and for all eternity.