temperamental

/T EH0 M P R AH0 M EH1 N T AH0 L/
adjective
  1. 1

    (notcomp) Of, related to, or caused by temperament.

  2. 2

    Subject to changing and unpredictable emotional states; moody, capricious; sometimes used figuratively to describe user-unfriendly or unstable machines or software that are either complicated and/or have poorly written instructions and are subsequently difficult to operate.

Source: https://en.wiktionary.org/wiki/temperamental