Greedy versus lazy quantifiers

.* is greedy: it takes everything, then backtracks. Use .*? for the shortest match, or better, a negated class like [^"]* which cannot cross the delimiter at all and does not backtrack.

Catastrophic backtracking, usually from nested quantifiers like (a+)+. Rewrite so each position has one way to match, or use a library with a linear-time engine. Input length alone rarely causes it; ambiguity does.