Luk 10:38-42 Now it came to pass, as they went, that he entered into a certain village: and a certain woman named Martha received him into her house. And she had a sister called Mary, which also sat at Jesus' feet, and heard his word. But Martha was cumbered about much serving, and came to him, and said, Lord, dost thou not care that my sister hath left me to serve alone? bid her therefore that she help me. And Jesus answered and said unto her, Martha, Martha, thou art careful and troubled about many things: But one thing is needful: and Mary hath chosen that good part, which shall not be taken away from her.
Martha is careful and troubled about many things. Remember from the earlier entry that "careful" can also mean anxious. So Martha is anxious and troubled and stressed out about what she's doing.
Martha isn't doing anything inherently wrong or evil. She's offered her home to Jesus and his followers, which must have been no easy or cheap task. I read it probably wasn't particularly safe, since He wasn't all that popular with the authorities. So Martha is doing a good thing! But she's doing it at the expense of a better thing, which is listening to Jesus and being obedient to Him. She was worried about her domestic duties and that worry kept her from paying closer attention to God. Meals are worldly, God is eternal.
Of course this doesn't mean we shouldn't feed ourselves, family, or friends. But to worry about such things and cause undue anxiety about tasks and things with no eternal value is a waste of time.