Umm.....it all depends....
If you plant is repeat flowering, then yes, you could generalize and say pinching would do good..not necessary making better as such but at least giving you growth that has 'different ages'..thus flowering may become more staggering rather than in one big flush. And ...pinching may delay the flowering giving the green growth more time to harden off/mature and it will the be able to take the weight of the new growth and flowers better.
I would not pinch anything that has naturally very singular stem growth habit..pinching will just ruin the looks....and bulbs, they will generally just flower once and that's it for the year. Anything that has long flower stem.. proud growing and separate from the main plant I would not pinch neither.
I don't tend to pinch the growth off from that many plants...they usually do well enough without the extra effort...BUT....there is few that I always do...many bedding plants. Buzy lizzies, fuchias, petunias etc. I pinch all the flower buds off in their early stages..not allowing the plants to flower for some while and because of that, they will try to make more and more new branching growth to make more flower buds...once I stop pinching, the plants are good size, robust and I get much more better quality flowers. I carry on pinching the growth until the plants have filled up their containers/baskets.
It is quite difficult to give that general answer....it really does come down to learning of your plants needs.
