When diluting acid, always add amount of acids to large amounts of water. Name one reason why we have this rule? :)

Well, acids are in powder form in the laboratory before preparation. If you have large amounts of acids and small amounts of water, you'll have a concentrated acid. (acids do not behave as acids unless they are dissolved in water, unlike bases). However, if you add the acid to the water, the concentration would be as small as possible.

Also, the reaction of the powder acid plus water is highly exothermic (releases a lot of heat). If you are working with a plastic basin, it could melt! (well, not sure of that though)

Besides, adding water to acid will produce fumes of acid (acid in vapour state). And the acid fumes are suffocating.