If someone pisses you off or disappoints you, that is not an issue of them purposely doing things because you are easy to take advantage of, you are stupid or that you don’t deserve respect.
People doing things to upset us is decided by us. If someone disappoints us, it’s not that they have done something that directly hurt us, it’s that we sub-consciously feel we deserve to be taken advantage of or disappointed.
We set our own expectations of others, and of ourselves and what value we have as a person. If someone does piss you off, or does something that upsets you, stop and see if you can see it as entirely their loss. If you are upset by their actions it may be that you feel entirely deserving of their disrespect, scorn or insults.
If you are comfortable with who you are as a person, and you know you’re doing good things and doing things a valuable person does, no body can upset you and definitely nothing they say (or don’t) can affect you.
The reason they may be acting the way they do may have ZERO to do with you, but it could be that they’re having a lousy day, they got some bad news recently, or they may just be miserable people. None of that has anything to do with you.