I do a lot of dairy work. It all boils down to what you're used too.....
Like the man said, its all about what you're used to.
Preparation for various types of work or situations helps a lot, too.
One company I worked for had a few lucrative service contracts. A tire "empire" chain, a breakfast 'dude' chain, and a pizza chain that Jabba hangs at.
Sounds pretty cool (free lunches) until you have to deal with grease and oil (the cooking type and the automotive type) all over you and your tools. I had to get a second set of hand tools, one for these type of jobs and a 'clean set' for everything else. And keep a complete change of clothes in the van in case you have both clean and dirty jobs in the same day.
We also would do work for a landlord whom we nicknamed 'slumlord'. Mostly wiremold work to bring units up to minimum safe levels after code enforcement paid a visit. Lots of cats, dogs, dirty diapers (children's and adults), birds, roaches, and rats. Just make sure you wear disposable shoecovers so whatever you step in doesn't end up in your truck, office, or home, and wear a NIOSH 95 or better mask because a lot of these situations are health hazards for you. Keep hand sanitizer in your truck, too.
And then there's the lift stations. New lift stations were fun, I liked doing control work, but the ones that had been in service for a while took a little stronger stomach. Prepare the best you can, and you'll get through.