What does the cheer up bonus do?

As the first Guest responded, it gives you a bonus if you lost the match only, the other glove offers a bonus for winning. It is up to you which you want to wear more. TO see their said ability you must go to the equipment storage in the main lobby via the bottom to the left selecting the Bag Icon to see all equipment, select the gloves tab and then select the glove you want to check out, you can see any pieces stats no matter if you have it or not.

If you scroll over the bonus it reveals a percentage that is applied to your score on all games you lose.