Stressed, a little confused on whom to tip and how much. but some workers say that extra 15% or 18% or 20% is the only way they make ends meet. vanessa yurkevich reports. >> reporter: this screen is stressful for many. does the flip of screen feel like a lot of pressure? >> it does. and they give you options like 10, 15, 20, even like uber, dash and grubhub, all of it. everything is tip, tip, tip. >> reporter: do you think tipping has gotten out of control? >> yes. >> reporter: tips are part of american culture meant to be a thank you for good service. but today more and more americans are con...