Is putting "Hi" as the subject of an email appropriate?

Its just that a lot of "spam" starts that way, you are curious if someone you know really wants to say hi so you open it up and whamo there comes more spam and sales stuff

You could put something like "semi formal dress required". Saying "appropriate" is somewhat insulting to the people who know how to dress for a wedding, NO, you are not the only one who has seen people come to a wedding dresses inappropriatly. I went to a wedding last summer. It was beautiful, a nice garden wedding with a reception in a pavillion over the water. This group of people showed up in shorts, tanks and flip flops. They had been out at the lake for the weekend and did not have the courtesy to go and change, came in smelling like beach and sun tan lotion. FLIP FLOPS at a wedding. There I was in a chiffon sun dress, just thinking WTF?? They looked out of place, but did not care. There was another wedding I went to where a few people did not bother to attend the ceremony, but showed up at the reception in jeans..looking like they were going out to a club! It was terrible. People do not always respect the fact that a wedding is more than a party. I totally see your point. Put "semi formal dress" on it and you should be ok.

Why would it be considered bad? It all depends on who the email is directed to. If it is for friends, or family -- I don't see it as a problem. If it is something directing a job, bill, school, etc. it should be more formal.

Nothing is appropriate anymore... The Patriot act passed, Jerry Springer is a household name, they allow "*****" and "***" on the radio, movies promote homosexual and cross-ethical relationships, my soup has a fly in it......

i do it just cos its short and easy