There's a lot of confusion between Memorial Day and Veteran's Day
and even though everyone means well, sometimes the message doesn't get through. Memorial Day is the day for remembering those veterans and non-combatants who aren't with us anymore. This (probably) means your grandparents and great-grandparents, and the people whose names are inscribed on the statue at the center of your town square.
There's an old song that goes "All gave some, some gave all." Memorial Day is more than just a day for barbecues and picnics; it's a time to remember those who did give it all so you have all the freedoms you have today. There's a patriotic spirit that runs through the history of this country, a spirit that the life of one person just isn't as important as creating a better life for all people. That's what those fallen soldiers were saying and thinking, and it's why we honor them.
If you see a living veteran today, it's fine to thank them -- you should thank them every time you see them. Today you might want to take a moment to ask them to recall a fallen friend or comrade.