Tim Challies wrote an article on why not to wear crosses. He showed that it was a form of worshiping an image. By relying upon an object to help you focus on Jesus, you're actually worshiping the object. Do you agree?
I was not aware of the Challies' article but looked it up. Challies did discuss his dislike of crucifixes and linked it with object worship – specifically a cross that depicts Christ still hanging on it versus a bare cross. I can agree with Challies there because of the associations of crucifixes with the Catholic teaching that Christ is required to be sacrificed anew, over and over again (the mass). Christ was offered once for all (Hebrews 7:27, 10:10). In a different article, Challies does lean more toward avoiding the use of crosses in churches or wearing them as jewelry. Do I agree with him on this point? mostly not. Can the cross be worshiped? I don't doubt that it can and it certainly should not. But physical objects are used in the bible to assist us in worshiping God. I'll give one quick example. Both baptism and communion are physical acts (communion involving objects) which are both commanded for the church and are physical portrayals of spiritual things. The bread and the cup are very graphic, tangible and consumable objects which help us remember the Lord's death in our place and proclaim him until he comes. Should we worship anyone or anything other than God? Absolutely not. But does having a cross cause us automatically to be on a slippery slope to idolatry? I say no.
What do you do when reading the Bible, praying to God and worshiping the Lord seems boring, ineffective, and/or not a joy?
First, let me say that every Christian struggles with the question you are asking repeatedly. Each one of us goes through “dry” times when our Christian life seems dull and our hearts seem cold. You are not alone. The first thing to do is be honest with the Lord about the situation. Confess your dullness to him. Ask him to forgive you and to give you grace to understand the joy of your salvation again, to understand more of who he is and what he has done for you in Christ. Ask the Lord to showcase any hidden sin that you might be holding onto.
Second, Christians are to be in fellowship with other believers. A lot of times when we feel dry, we have typically neglected making either our own spiritual disciplines a priority in our day (like the ones you mentioned above – prayer, Bible reading, worship – or we have neglected the fellowship of the saints. Has there been too much distance between you and the body? I often need to be around other believers more and more who love the Lord as their prayers and encouragement lift me up. Sharing these things with others and praying together is powerful at breaking the cycle of doldrums. Often, but not always, unconfessed sin will cause us to want to shrink back from the fellowship. Another diagnostic is to address whether you have been serving anyone or not. When we are not serving others, we become very self-focused and that inevitably leads us to gloomy thinking. Depression, stress, etc. can be real challenges that have no direct bearing on our own sin. Bottom line, it's always the right thing to communicate your heart to God and to ask him to increase your joy in him. Hear the voice of your Shepherd reading the word and hearing it preached. Music is a great instrument God has given us as well to focus our attention once again on him.