What was your greatest investment???

Mine is a toss up between my camera and my sewing machine!!! Both bring me joy and produce LOTS of goodies and they both make me money so that's a bonus also ; ) if I had to narrow it down it would be really hard!!! I use them both daily but as much as I love my sewing machine I hate it also lol we really have a love hate relationship it loves to make me mad and I hate it for it lol!!! If I could produce products like I can produce photos it wouldn't be such an ordeal BUT I've only been sewing for a year and I've been doing photography for over 6 so in 5 years I'll let you know if I still hate my sewing machine or not!!! What is your must have investment???