ERJ-170 FO reported encountering wake turbulence departing LGA in trail of another aircraft.

Narrative

We were originally number 16 in line for takeoff. It was a beautiful VFR day. LGA was launching everyone quickly. Every other clearance was line up and wait; be ready for an immediate takeoff. We were expecting the same thing. We were given the same clearance. Then; while Aircraft Y was still on the runway; Tower gave us a takeoff clearance. I should have said unable. It was Aircraft Y; so I knew there was a possibility of wake; but it wouldn't be like the wake of a heavy jet. I slowly advanced the thrust levers to delay as much as possible and we took off. 100 ft. off the ground; we did fly right into their wake turbulence.I am seeing more and more limits being pushed. Separation requirements were met according to their standards. The other aircraft was off the ground past the end of the runway by the time we started our takeoff roll. But I don't know why it has to be so close. This worked out fine; but I think we are pushing limits too much and an accident is going to happen sooner rather than later. As the pilot group; we need to say unable if we are not comfortable with a clearance from ATC. Just because they give it to us; doesn't mean we have to take it. If we start saying unable more and more; they will stop giving such tight clearances.