I've no doubt the engineers at Facebook and SAP find plenty of interesting problems to fill their day. The macroscopic problems that both companies are solving in their respective niches are... What?
It's not a startup versus enterprise thing. It's (partially) a question of whether the interesting propellerhead problems are in aid of an interesting larger goal.
The macroscopic problem that SAP works on is collaboration within large organizations. How to make processes more efficient while reducing bureaucracy. I'm not saying they're doing a good job of it, but that's the task. It's a big, very interesting task.
Then you have no perspective of the problems SAP is solving.
SAP is solving tons of big data problems with a variety of interesting data modeling and analysis.
These are wildly interesting problems. They are as interesting in a small startup environment as they are in a large company.
There seems to be this real us versus them attitude with people who identify with startups.
People that work in SAP are no different than startups. Many people that work at SAP come from startups.