I usually just peel an orange and eat it like candy. I used to smother my grapefruit with powered sugar but now I eat it straight or eat it mixed with orange. I can eat a pretty big bowl of this in one day. It makes me feel sunny and cheerful.
Here is a fun video on how to peel citrus. I don't cut out the segments - I just peel and chop. Make sure you use a freshly sharpened knive.
I got this one at Walmart 3 years ago for $30 and I use it on the JAHenkles knives we got as a wedding present 27 years ago - and it works great! A must have if you are constantly chopping up plants to eat.