A few comments in no particular order:
1) You are still young and some time moving sideways isn't always a bad thing. It is okay to take a short break from your regular training to do something else, if this satisfies your curiosity/sanity.
2) Changing routines necessitates some downtime where you get up to speed on the new sets/reps and/or exercises. This isn't necessarily a bad thing but make sure you account for it when you're looking at optimum progress.
3) A bunch of sets/reps written on a monitor screen don't make the lifter.
4) Little progress is always better than no progress (unless number 1 applies of course).
5) Some people cope with routine changes much better than others. Some don't and require a mental/physical build up. Which are you?
Originally Posted by tank
If a program does not inflict enough stress to require a deload, does the program's efficiency become questionable?
This is probably my fault.
1) In terms of absolute progress, if it's working then stay on it.
2) In terms of fun/curiosity then sure switch it up for a while.