It doesn't pay off to be meek with US
First of all, it should be noted that Iran has long list of contentions and grievances vs US. It all started with 1953 coup orchestrated by US (and UK) which was followed by long rule of last Shah, Mohammad Reza Pahlavi. Pahlavi is now considered to be corrupt and inefficient ruler, who gave Iranian oil and other resources to Western powers, spent money on extravagances and unnecessary Western weapons (for example F-14 Tomcat, very expensive aircraft at its time) while majority of Iranians languished in poverty. Anyway, Iranian Revolution of 1979 brought Shah down, Americans naturally were not amused, there was famous hostage crisis etc so relations between new Islamic Republic ans US got of to a bad start. Add to that new government disliked US policy towards Palestine and Israel (considering US to be under control of Zionists) , despised Gulf monarchies (Sunni, opposed to chiefly Shia Iran) for their servility towards US and fake outdoor piety (coupled with debauchery behind closed doors) and wanted to build new self-reliant society. Then Iran-Iraq war started, with Iraq getting lot of support from US, especially after 1982.
Anyway, with all this said and done, Iran considers US as its natural enemy, with irreconcilable differences, and a toxic influence in Middle East and whole world. Indeed, US is Great Satan, from its decadent culture to its aggressive foreign policy. Therefore, it is official goal of Iran, often stated publicly, to remove US from its neighborhood (Middle East).
Considering that Iran is not only enemy of US, it should be noted that Americans love to "bring democracy" and often use protest, coups, or outright military intervention to fulfill their strategic goals. In last few decades this happened lot of times - Iraq, Libya, Yugoslavia, Afghanistan, Ukraine, attempt in Syria, and numerous smaller interference all over the world. Most of the time, countries targeted by US attempted to negotiate, and US used foot in the door technique to impose its own interests and legitimize its presence. Iran therefore concluded it does not pay off to play nice with US, i.e. that US respects only raw power . Country must have capable military, and not be afraid to use it aggressively, not allowing US slightest incursion into its territory. Btw, North Korea has similar policy, and it was so far also successful for them, because it prevented US military intervention. Unlike North Korea, Iran has no nuclear weapons (at least officially) so they feel themselves more vulnerable and therefore they need to act more aggressively. Recent example was killing of General Soleimani - Iran responded with missile strikes on US airbase (something that much more powerful militaries would not attempt) in a clear example of escalate to deescalate strategy, which worked this time. So, as a conclusion, it is very unlikely that Iran will back-down and ease tensions with US, at least not until they acquire weapons of mass destruction and feel more confident US would not attempt to interfere in their internal matters.