Dilution is intentional, not accidental. Shaken cocktails dilute roughly 20-25% by water weight in 12 seconds. Stirred cocktails dilute 25-30% in 30 seconds. Use less ice surface area (one big cube) and the dilution is slower; use crushed ice and it's faster. A perfectly diluted Martini is not 'strong' — it's balanced. If a guest complains a drink is too strong, it's likely under-diluted, not over-spirited.