Is it considered a sin if I post expressions of love and emotions on social media without my mother's knowledge, given that I sometimes need to vent my feelings in this way?

Placing phrases of love on social media can convey a wrong message to those who see them, entice actions displeasing to Allah, and become a reason for falling into the snares of Satan. Obeying the mother by not posting these phrases is obligatory because she has only commanded what is good and is keen on the questioner's religion and morals. "Venting" can be achieved through permissible means.