Answer:
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
There are millions of me. I am very small but when moving fast I am deadly.
Die without me, never thank me. Walk right through me, never feel me. Always watching, never speaking. Always lurking, never seen.
What has 3 feet but cannot walk?
My love, when I gaze on thy beautiful face. Careering along, yet always in place, the thought has often come into my mind. If I ever shall see thy glorious behind.
This food is a tortilla filled with cheese and sometimes chicken before being heated or cooked.