I have seen a lot of Muslims refuse to even say happy Valentine’s Day to their friends, so I wanted to double check.

Such kinds of celebrations have become social occasions. Therefore, there is no objection to participating in them provided a Muslim does not do anything that contradicts the Islamic creed.

It is lawful [halal] in Islamic law to specify a day for renewing lawful love between spouses or among friends and family. This is because there is nothing in Islamic law to prohibit this. However, this occasion must not be called "Eid" (feast), but " Love's Day" (Youm al-Hob).