Given a category and a set of five words, find the word from the set that does not belong (i.e. is the least relevant) with the other words in the category. Words are separated by commas.

Category: emotional status 
Words: down, emotional upsets, disgusted, shameful, sliding
sliding

Category: mode of transportation 
Words: train, spider, wave, fly, drive
spider

Category: computers 
Words: image, format, reception, file, folder

reception