1) A phase pistol will never leave you to chase after some alien woman
2) It won't make snarky comments when it's tired
3) It doesn't care if you're feeling gloomy. Or even writing letters to all the women in San Francisco
4) It gets itself (and you) OUT of dangerous situations rather than into them
5) It never pulls rank
6) The Captain doesn't get fed up if a phase pistol wants to spend all its time with you instead of watching water polo
7) You never have to worry about it getting stranded somewhere
8) If it gets hurt, there are plenty of others just as good
9) Practice really will make perfect
10) Nothing you say can ever upset it

1) The warp engine is never in a bad mood
2) It doesn't mind if you meet a beautiful alien
3) It doesn't laugh at you when you're stuck semi-naked in a swamp with an annoying princess, or when  you get pregnant, or when someone else's wife is hitting on you, or...
4) You can fix its problems
5) It's always ready to make soothing noises, even at 2am
6) Attacking it with a spanner actually helps
7) You understand how it works
8) It doesn't blame you for getting it into trouble
9) It never flirts with other people
10) You will never say anything to reinforce its fundamental insecurities