I’ve had two roommates who worked at TJ’s. They’re encouraged to be friendly and chatty but it’s not forced or mandatory. Most of the employees seem happy because they do enjoy their jobs, insofar as one can enjoy that sort of work. Protip: You can ask to try just about anything in the store and they’re supposed to open a package for you to sample. Doesn’t work for liquor though.
At Whole Foods any floor employee (well, not the ones on registers or demos) is required to escort customers all the way to whatever item they ask them the location of. I always feel terrible pulling them away from their shelf-stocking or whatever duties — just tell me the aisle number and I’ll find it! I don’t want to be a hassle!