Many people hated the Dungeons because they were cold and dingy, always tinting the air with dampness and potion fumes. But that was what Severus Snape loved about it so much! It wasn't stuffy and humid like he guessed the Gryffindor Common Room was like and it wasn't close to the kitchens where you were constantly overwhelmed with the scents of food like he presumed the Hufflepuffs were. He had no clue about the Ravenclaws and he held no opinion for them but he guessed that they would be constantly in touch with books both day and night. That was too much for him.
No, the Dungeons held a certain place in his heart. A comforting bubble that nobody could burst; not even the pesky Marauders were able to.
He'd find himself constantly over a cauldron, his nose picking up on tiny mistakes just by one sniff. The scent for each potion - except Armotentia - would give away what was wrong or right about it. Many held disdain for him due to his greasy hair but how could one combat that when the potion fumes and dingy Dungeons constantly made them less than desirable? He didn't care regardless.
The Dungeons were his happy place.