Sometimes, I just get in a hurry and don't think. When trying to take the top off my coffee mug, I all too often put the opening right next to my shirt on my chest for some 'leverage' and duh, coffee stain! I'm learning. Much better when you make sure the opening is to the side, when taking off the lid. ;-)
Another helpful tip is to use a collapsible koozie for your coffee mug. Keeps your coffee hot longer, is a good drip catcher, provides protection for your table, is quiet when you set your mug down, and it feels better in your hand when you hold your mug.