Anonymous cards, notes or flowers could also cause unintended damage she said, no matter how good the intention.
"Some people can feel quite disconcerted at the thought of somebody watching or noticing them, or having feelings for them," Beck said.
"It can be perceived as disturbing in a workplace, where most people are simply there to work and get along."
"If it is unrequited love, and you might discover that on Valentine's Day, and there starts to be repeated and unwanted contact then that can constitute sexual harassment and a person could find themselves with some serious legal problems for misconduct," she said.
Office policy around work relationships should also be considered with Beck saying this could affect your work.
"You might be obliged to report the fact that you're having a close personal relationship," she said.
"So that there's no suggestion of conflict or favourable or unfavourable treatment of other people in a team."