Not sure if you are implying that by adding tipping you will get the employees to be more personable/pleasant. If you are:

I can assure that is not the case. I would love to know what the secret is to getting people to show an ounce of enthusiasm. A family member has a bakery and getting the front of house to engage with the customer at all is like pulling teeth, and this is an above-minimum-wage job with tips. They aren't on "commission" (it's been tried) but their tips are directly influenced by the ticket price (obviously).