It sounds crazy but I wanted to start something similar to Linkedin way back in 2004 when facebook came out and we already had other personal social networking sites like hi5, friendster etc. I thought it would be cool to do it for professionals and career industry. Ah, my loss. Never acted on it :)
... but someone else did, and now it is a successful project. What discouraged you?
There are a few that popped up over the last year, that really made me think _I knew there is going to be demand for it_, but I deprioritized, and seeing them now grow at rocket speed is gut-wrenching
Write a database, specifically a time-series database.. but it has been on back-burner long enough now.