Sending letters has become a history now. We are totally habituated to sending emails now. Since there are no letters, we miss envelopes too.
In the era of letters, envelopes were the indication of the subject of letter. People could understand it , most probably due to the color of envelopes. Pink envelopes means it’s a love letter. Brown envelope means it’s an official letter. White envelope is used for sending resumes. Different company use envelopes as promotional envelopes by printing their logos on it. Even various color envelopes were used for sending greeting cards. Greeting card envelopes were also had different sizes. I was so fascinated with these different sizes of envelopes, that I still have few greeting cards along with its envelopes. I do have lot of memories related to these envelopes too and that’s why they are very close to me.