Actually I feel that different gear has different "feelings".
With test it gives me the extra boost and drive to force out a few more reps.
Tren strength is different from test strength. Test strength feels more raw and aggressive. Tren strength feels more unified and artificial, that my whole body is working as one to lift the weight. dunno how to describe it. maybe someone more eloquent than me can chime in.
npp not much extra strength but greatly reduced muscle soreness.
I think alot of it comes down to the effect its having on your emotions and mental state aswell as your diet in combination.
I've been on tren test for 3 weeks and i've just kinda been whatever, 2 days in a row 400g carbs and i hit quads for nearly 90 minutes yday with most ferocity and enjoyment in month's.
When people get on gear it tends to come with the oh well i'd better invest in x, y, z supps and start eating appropriately for my goals when they should have been all along.
The mind is a powerful thing, half the things you achieve on gear come simply because you believe it's worth attempting now.