Mug

*Why do mugs have concave bottoms?
The mug bottom is often not flat, but either concave or has an extra rim, to reduce the thermal contact with the surface on which a mug is placed.

• Cylinder

• Select all faces from top
• Extrude

• Go to Top view > Rotate

• Insert Edge Loop
• Shift + Ctrl + Multi-Cut works like Edge Loop Tool

• Pipe

• Delete half of the pipe

• Select both then Booleans > Union

• Multi-Cut