I think mental toughness occurs from being a positive person in general. I'm basically laughing at a lot of things that look like it's giving me a hard time now and over all the little things as well. I've learned to channel my anger or frustrations these days from just keeping it there and not letting it turn into a grudge by calling the other person crazy! By labeling the person to be crazy who is really ticking me off for any reason, I feel pity on that poor soul and so I don't need to feel any grudge for him or her. I can hope for him or her to get better and communicate in that manner while having room to laugh about it behind their backs later and no one else having to know about it.
When someone else does that to me, I naturally give him or her a hard time. It's just how it's usually been for me. There are a few rare exceptional individuals I came across of all the people I know. It's like grinding for sunken treasure on a fun RPG and coming across a valuable item will not happen as often in percentages because of the common ones showing up. They exist out there like a gorgeous woman willingly chasing after an ugly man! It's just that the percentages aren't that high but if an ugly man does enough searching, then there he has it going for him.