On mobile so formatting might get messed up.

I understand that at sitdown restaurants it is courtesy to tip, and I make sure to give a good 20% tip every time I go to them, but here are some situations that I ran into last week that make me question whether I should always tip.

1. I got $3.50 bubble tea, and saw the barista make it in 30 seconds right in front of me, and when I swipe my card I get an option to tip. I saw no reason to tip.
2. This happened in another, similarly priced bubble tea place. After filling out $0 as the tip in the receipt the waitress looked at the receipt, frowned, and then proceeded to make the bubble tea. It took 2 minutes to make and I walked up to the counter to pick it up, as all customers do. I dont think such service calls for a tip.
3. I ordered a takeout udon bowl at a normally sitdown restaurant, and it was ready in 3 minutes. Because no one waited me and all that happened was an order was filled out, I dont think I need to fill out a tip.

AITA for not paying tips in these scenarios?