FEEEEEEELINGSSSSSSSSS!

Okay, now that's that's said, time for a real answer:
I'm a huge proponent of integrating the study of feelings and emotions into history. I think one of the greatest disservices we can do as historians is to view the past dispassionately. It can be remarkably easy to let our knowledge of history influence our understanding of a particular moment. I think it is particularly easy to do this in regards to feelings and emotion states.
The sociologist Deborah B. Gould coined the term "emotional habitus" to refer to a particular socially-constructed way of being and feeling. I think this is a really helpful framework for historical study. I personally often talk about "feelings over facts" as being another useful framework for understand emotionally-charged historical events.
I find the study of feelings to be hugely important for my own research and pursuit of knowledge. I study the AIDS crisis, which is 1. hugely emotionally charged, and 2. is closely linked to the current, ongoing AIDS epidemic, making it harder to situate as a distinct historical moment. Some ways in which "feelings over facts" has been useful:

1. There was a widespread rumor-driven fear amongst gay men (and some lesbians) that the government was going to round up people with AIDS into concentration camps, tattoo them, or use an HIV test as a kind of homosexuality test to exclude gay men. Obviously none of that came to pass, and now it seems a bit ridiculous. Even at the time, I don't think all or most gay men truly expected them to happen. However, these fears definitely existed, even if only in the shadowy bits of people's brains that hold irrational fears. Those irrational fears were real and valid emotions and they informed how many gay men and lesbians thought and acted.
2. Many lesbian AIDS activists were passionate on the subject of lesbians and AIDS. Now they are usually derided as a joke (and often were at the time as well.) Although we now know that woman-to-woman transmission of HIV is extremely rare/nearly impossible I think it's wrong to judge them on that score. Many of these activists came from a background of the lesbian health movement and general concern over women's health. They had to confront the very real problem of the medical establishment's general ignorance of how AIDS impacted women. Additionally there was absolutely no study of AIDS in lesbian populations and communities, despite the fact that lesbian identity could overlap with other risk categories. Add this to the medical establishment's general indifference/ignorance of lesbian sex and sexuality, you had a lot of angry lesbians frustrated about AIDS. Now we look back and laugh at these women for "trying to get in on the glory." When situated in an emotional context, however, the actions of lesbian activists becomes much clearer.

I think emotions play a massive role in understanding history. Not even in the simplistic sense of "individuals have emotions and those emotions make them do things or not do things" but in the sense that events have an emotional context. People experience events through their feelings. Even though emotional are often "irrational," they exist for a reason, and I think are just as relevant or helpful for understanding historical events as anything else.
**apologies for any grammatical weirdness; it's late and I'm about to go to bed.