We see a lot of folks doing tons of extra stuff after workouts. We're cool(ish) with that. Doing a little more running, lifting, rounds, reps, weight and etc. can be very helpful over the short term. We suggest it in some cases. However, you need to be careful. This sort of thing can wreck you on every level (body, mind, soul, relationships, finances, motivation) if you keep it up over the long term. Sometimes you just have to TYT (trust your trainer) that the workouts we are piling on you daily are going to do the job. Need proof of this? Just look around a little next time you're in. We are "gettin it done" down here at GPP (can I get a WOOT and then, another WOOT?).
Extra credit (more lifting, running, etc.) is great if you are using it to improve in areas of weakness, or if you have healthy goals beyond normal GPP. But to do it right you need a plan. Can't just go willy-nilly into WHATTHEHELLEVER for HOWTHEHELLEVERLONG and expect to get good results. When planning, make sure your EC includes clear: intent, programming, progression, markers for success, balance and recovery time. The last two are the most often ignored. They are also the most important.
Fitness is NOT like math. 1+1 doesn't always = 2 in fitness. Sometimes adding a workout will negate the workout you just did, so 1+1 = 0 here. Worse, sometimes adding a workout can TAKE AWAY from the benefits of BOTH of the workouts you just did, so 1+1 = -1 in this case. That SUCKS.
If you need help strengthening a weakness, please come talk to one of your trainers. We've been doing this a while. We can help.