Thank you. Yes. Nethack is a great comfort game.

Dungeon Crawl Stone Soup is fantastic for me, too. You can play it through your browser (or download it) here.

I have to say, though, there's nothing quite like a game of Rogue. When I play it I'm instantly transported back to childhood. Rogue was my first real video game obsession as a kid. I found it on my grandfather's Apple IIgs and was just blown away. I remember being so enthralled by how deep it felt at the time. I had transcribed the commands to a piece of paper so I didn't have to consult the in-game docs constantly. I was terrible at it, and never got anywhere close to beating it back then, but even dying was fun. You can play it online here. Type ? (or F1) to see the list of commands.