"What's with ___?" is a casual way to ask why something is happening. For example, if one of your coworkers is yawning a lot, and you want to know why, you can ask:

What's with the yawning?

This means "Why are you yawning so much?"

"What's with ___" is used in informal spoken English and when chatting online. It doesn't have any strong positive or negative associations.