Of course, tipping of any amount should be encouraged.

There are cases though, like a large delivery, that a small tip for a lot of extra work may be inappropriate.

The secret to this is try to use body language and short words to express dissatisfaction without being mad or critical, try to encourage the customer to part with a little more.

“Just to let you know, with your tip and what I get from Uber, I’ve only made $3 an hour for this…”

Tact.