We had some embedded bolts in our pool deck that were part of an old diving board installation. They laughed at a dremel using heavy duty cut-off wheels. I bought a cheap 4 1/2" angle grinder with cutting discs and it made short work of the bolts.

Using the right tool for the job saves much time and pain. (More recent example: trying to cut some HVAC ducting in-situ between floor joists. Started by trying good quality aviation snips and ended up with a sore wrist before even getting close to finishing one cut. Bought a reciprocating saw and the rest went soo much more smoothly.)