When you massage someone, the levels of oxytocin go up in the brain, and oxytocin is one of the chemicals that drives attachment.
When dogs and humans make eye contact, that actually releases what's known as the love hormone, oxytocin, in both the dog and the human.
It turns out that we literally don't empathize unless we're physically present - that the oxytocin, the famous "tend and befriend" hormone is not produced unless we're present with all five senses.
That's what falling in love really amounted to, your brain on drugs. Adrenaline and dopamine, oxytocin and serotonin. Chemical insanity, celebrated by poets.