The feeling of nostalgia is a difficult feeling to explain. Nostalgia is a feeling that can only be described as bittersweet. There are things about feeling nostalgic that are great and things that are a little bit sad.

Nostalgia brings back memories of times long gone, times that can never be revisited again, which is kind of an upsetting feeling. Many of those old memories were the happiest of times for some. Over the years, things have changed drastically.

Technology has advanced in astounding ways, and the trends and fads are so different now than ever. It's fun to look back on what life was like even just 15 or 20 years ago, which is not that long in the grand scheme of things. Reddit's "Nostalgia" is a subreddit that contains nostalgic pictures of all kinds. There is something for everyone on here to satisfy anyone's desire for nostalgia.

Here are just 25 of those very retro images and moments that might make some people feel a little old.