Gratitude goes a long way.
Thank your friends for their consistency, balance, perspective, kindness and even their differences. You can never go wrong with practicing common courtesy . It doesn't have to be extravagant! A thank you (especially a face to face one) speaks louder than a thousand return gestures.
Also, a sidenote about thank: Facebook shout outs are nice but a personal handwritten card or letter and even better. An eye to eye conversation expressing thanks will grow your friendship by leaps and bounds in just a minute or two! No longer will it weird to be open and mushy with feelings after you take the time to do that! And what an awesome gift, the gift of gratitude!