If you're anything like me, you probably think the opposite of clinging is indifference. If I don't care, then I'm not attached, right? Wrong. From a Buddhist perspective, the opposite of clinging is aversion. Attachment is "an exaggerated not wanting to be separated from someone or something". Non-attachment doesn't mean you don't care; in fact, non-attachment is equanimity - it means you can truly feel love without expectations or demands or strategies about outcome. Byron Katie says real love is "wanting someone to want what they want", which makes me wonder because most of us learned the opposite - that love means "wanting someone to want what I want them to want".
So don't be afraid to care about a person, a cause, an idea. And when they or it don't turn out the way you expected, you can see the depths of your attachment and begin to work with it. You'll start to see that often the real cause of anger and frustration is not getting what you want, and you can begin to feel receptive to different possibilities and humbled by the way life constantly doesn't turn out the way you planned. It's only when we can see our clinging and attachment that we can begin to see our suffering and longing, and through the application of compassion and patience towards ourselves we can find freedom from our struggles.
"What happens when we become Buddhist is we think, “Oh, I shouldn’t be attached, I’ll become renounced” and you walk around like some hopeless person, “Would you like tea, Robina?” “Oh, I don’t care” “Would you like coffee?” “Oh, I don’t mind” … This is called indifference and it’s revolting. Don’t be indifferent please!" Venerable Robina Courtin